[
  {
    "folder": "meerkat",
    "first_image_desc": "Two meerkats are facing left with heads close together.",
    "last_image_desc": "Only one meerkat remains on the left facing left.",
    "challenge": "Occlusion",
    "caption": "The right meerkat moves out of view to the right."
  },
  {
    "folder": "knife",
    "first_image_desc": "Hand holds a knife above a head of napa cabbage.",
    "last_image_desc": "Knife slices through napa cabbage as hand holds it steady.",
    "challenge": "Dynamic motion",
    "caption": "Knife slices cabbage into thin strips."
  },
  {
    "folder": "butterfly",
    "first_image_desc": "Butterfly perched on a yellow marigold flower.",
    "last_image_desc": "Butterfly perched on a yellow marigold flower.",
    "challenge": "Near-static",
    "caption": "Butterfly remains still on the yellow marigold flower."
  },
  {
    "folder": "person-hand",
    "first_image_desc": "Person in white outfit stands with arm at side.",
    "last_image_desc": "Person in white outfit extends hand forward.",
    "challenge": "Linear motion",
    "caption": "Person extends hand forward."
  },
  {
    "folder": "elephant-apple",
    "first_image_desc": "Man holds apple near elephant with raised trunk by water.",
    "last_image_desc": "Man throws apple toward elephant with open mouth and raised trunk.",
    "challenge": "Dynamic motion",
    "caption": "Man throws apple toward elephant with open mouth."
  },
  {
    "folder": "person-sunset",
    "first_image_desc": "Person in water facing sunset with arms down.",
    "last_image_desc": "Person in water facing sunset with both hands on head.",
    "challenge": "Dynamic motion",
    "caption": "Person raises hands to head in the water at sunset."
  },
  {
    "folder": "child-run",
    "first_image_desc": "A child in blue and red runs on a dirt path in a field.",
    "last_image_desc": "The child is farther along the dirt path in the field.",
    "challenge": "Linear motion",
    "caption": "A child runs along a dirt path through the field."
  },
  {
    "folder": "woman-arm",
    "first_image_desc": "Woman in blue dress smiling with arms outstretched in field.",
    "last_image_desc": "Woman in blue dress facing away walking toward cows in field.",
    "challenge": "Dynamic motion",
    "caption": "Woman turns and walks away toward cows in the field."
  },
  {
    "folder": "kangaroo",
    "first_image_desc": "A kangaroo stands on grass facing left with head turned slightly forward.",
    "last_image_desc": "The kangaroo stands on grass facing more forward with head turned toward camera.",
    "challenge": "Dynamic motion",
    "caption": "Kangaroo turns its head to look toward the camera."
  },
  {
    "folder": "surfer",
    "first_image_desc": "Two people with surfboards start running toward the ocean.",
    "last_image_desc": "Two people with surfboards run further across the sand toward the water.",
    "challenge": "Dynamic motion",
    "caption": "Two surfers run toward the ocean carrying surfboards."
  },
  {
    "folder": "jog-tree",
    "first_image_desc": "Person running away on a leaf-covered forest path.",
    "last_image_desc": "Person farther away running on the same forest path.",
    "challenge": "Linear motion",
    "caption": "Person runs away down a tree-lined path."
  },
  {
    "folder": "walk-snow",
    "first_image_desc": "Two people walk away on a snowy forest path.",
    "last_image_desc": "Two people are farther along the snowy forest path.",
    "challenge": "Dynamic motion",
    "caption": "Two people walk forward on a snowy path."
  },
  {
    "folder": "rooster",
    "first_image_desc": "A rooster stands on a branch with head turned left.",
    "last_image_desc": "The rooster stands on the branch with head facing forward.",
    "challenge": "Linear motion",
    "caption": "The rooster turns its head from left to forward."
  },
  {
    "folder": "suv-road",
    "first_image_desc": "One SUV far away on a dirt road. Another SUV partly visible at left.",
    "last_image_desc": "Two SUVs driving away on a dirt road. Both fully visible.",
    "challenge": "Occlusion",
    "caption": "SUV drives onto the dirt road and follows the other SUV."
  },
  {
    "folder": "dog-grass",
    "first_image_desc": "A dog stands in tall green grass facing forward.",
    "last_image_desc": "The dog runs forward through the tall grass.",
    "challenge": "Dynamic motion",
    "caption": "A dog runs forward through tall grass."
  },
  {
    "folder": "car-highway",
    "first_image_desc": "Red and white cars drive side by side on a highway.",
    "last_image_desc": "Red car moves ahead of the white car on the highway.",
    "challenge": "Dynamic motion",
    "caption": "The cars are moving forward on the highway."
  },
  {
    "folder": "hummingbird",
    "first_image_desc": "Hummingbird hovers near pink flowers with wings blurred in motion.",
    "last_image_desc": "Hummingbird faces downward feeding from pink flowers with wings blurred.",
    "challenge": "Dynamic motion",
    "caption": "Hummingbird moves downward to feed from pink flowers."
  },
  {
    "folder": "duckling",
    "first_image_desc": "Yellow duckling sitting upright on grass facing left.",
    "last_image_desc": "Yellow duckling curled down with head tucked under body.",
    "challenge": "Dynamic motion",
    "caption": "Duckling lowers head and tucks it under its body."
  },
  {
    "folder": "skateboard",
    "first_image_desc": "Person on skateboard facing left with sun behind.",
    "last_image_desc": "Person on skateboard facing right with sun behind.",
    "challenge": "Dynamic motion",
    "caption": "Person turns on skateboard under bright sunlight."
  },
  {
    "folder": "woman-exercise",
    "first_image_desc": "Woman in pink workout clothes lifts right knee indoors.",
    "last_image_desc": "Woman in pink workout clothes lowers right knee indoors.",
    "challenge": "Dynamic motion",
    "caption": "Woman lifts and lowers right knee during exercise indoors."
  },
  {
    "folder": "walk-bench",
    "first_image_desc": "A person walks on a path near a bench at sunrise.",
    "last_image_desc": "The person is farther along the path near the bench at sunrise.",
    "challenge": "Linear motion",
    "caption": "A person walks along a path toward the sunrise."
  },
  {
    "folder": "dog-frisbee",
    "first_image_desc": "Two dogs chase an orange frisbee on the wet sand.",
    "last_image_desc": "Two dogs stand together at the water's edge with the frisbee.",
    "challenge": "Dynamic motion",
    "caption": "Two dogs run and catch a frisbee by the shoreline."
  },
  {
    "folder": "cyclist-road",
    "first_image_desc": "A cyclist is entering from the left on a rural road.",
    "last_image_desc": "The cyclist is centered and further along the road.",
    "challenge": "Linear motion",
    "caption": "A cyclist moves forward along a country road."
  },
  {
    "folder": "dog-soccer",
    "first_image_desc": "A black and white dog runs toward a soccer ball on sand.",
    "last_image_desc": "The dog runs left with the soccer ball in its mouth on sand.",
    "challenge": "Dynamic motion",
    "caption": "Dog grabs soccer ball and runs left on the sand."
  },
  {
    "folder": "penguin",
    "first_image_desc": "Penguin stands on rock with head upright in snowy landscape.",
    "last_image_desc": "Penguin stands on rock with head bent down toward chest.",
    "challenge": "Dynamic motion",
    "caption": "Penguin lowers its head to preen its chest."
  },
  {
    "folder": "man-lake",
    "first_image_desc": "Person standing on dock about to jump into lake.",
    "last_image_desc": "Ripples in water where person landed. Person no longer visible.",
    "challenge": "Occlusion",
    "caption": "Person jumps from dock into lake causing large splash."
  },
  {
    "folder": "burger",
    "first_image_desc": "Open sandwich bun with vegetables on a black tray.",
    "last_image_desc": "Burger patty partially out of view on the left sandwich bun.",
    "challenge": "Occlusion",
    "caption": "Burger patty moves left off the sandwich bun."
  },
  {
    "folder": "woman-rocky",
    "first_image_desc": "Woman stands on rocky ground with left arm lowered.",
    "last_image_desc": "Woman stands on rocky ground with left arm raised upward.",
    "challenge": "Dynamic motion",
    "caption": "Woman raises her left arm while stretching outdoors."
  },
  {
    "folder": "parrot",
    "first_image_desc": "Red parrot facing left with green foliage background.",
    "last_image_desc": "Red parrot facing right with green foliage background.",
    "challenge": "Linear motion",
    "caption": "Parrot turns head from left to right."
  },
  {
    "folder": "wakeboarder",
    "first_image_desc": "Person in orange vest wakeboarding near left edge of water.",
    "last_image_desc": "Person in orange vest wakeboarding farther right with water spray.",
    "challenge": "Linear motion",
    "caption": "Wakeboarder moves quickly right across the water."
  },
  {
    "folder": "dog-park",
    "first_image_desc": "A black and white dog stands on grass far from the camera.",
    "last_image_desc": "The dog stands much closer on the grass facing the camera.",
    "challenge": "Dynamic motion",
    "caption": "A dog runs toward the camera across the grass."
  },
  {
    "folder": "lion-yawn",
    "first_image_desc": "A lioness yawns with mouth wide open beside another lioness.",
    "last_image_desc": "Both lionesses rest with mouths closed facing the same direction.",
    "challenge": "Dynamic motion",
    "caption": "Lioness closes mouth after yawning beside another lioness."
  },
  {
    "folder": "cyclist-four",
    "first_image_desc": "Three cyclists ride away on a tree-lined path.",
    "last_image_desc": "One cyclist rides away alone on the same path.",
    "challenge": "Occlusion",
    "caption": "Cyclists ride away down a tree-lined path."
  },
  {
    "folder": "husky",
    "first_image_desc": "A husky stands on grass with mountains and trees behind.",
    "last_image_desc": "The husky lies down on the grass facing forward.",
    "challenge": "Dynamic motion",
    "caption": "The husky lies down on the grass."
  },
  {
    "folder": "city",
    "first_image_desc": "Blurry city skyline and beach with no people visible.",
    "last_image_desc": "Woman in blue top holds camera facing city skyline and beach.",
    "challenge": "Occlusion",
    "caption": "Woman raises camera to photograph the city skyline and beach."
  },
  {
    "folder": "silver-car",
    "first_image_desc": "Front of a silver car entering a railroad crossing.",
    "last_image_desc": "Rear of a silver car leaving the railroad crossing.",
    "challenge": "Linear motion",
    "caption": "Silver car drives across the railroad crossing leftward."
  },
  {
    "folder": "hand-water",
    "first_image_desc": "Hands apart under running water.",
    "last_image_desc": "Hands clasped together under running water.",
    "challenge": "Dynamic motion",
    "caption": "Hands move together under running water."
  },
  {
    "folder": "salad",
    "first_image_desc": "Hands holding two spoons above a bowl of fruit salad.",
    "last_image_desc": "Hands holding two spoons above a bowl of fruit salad.",
    "challenge": "Dynamic motion",
    "caption": "Spoons lift fruit salad upward from the bowl."
  },
  {
    "folder": "air-conditioner",
    "first_image_desc": "Remote control displays 21°C near an air conditioner.",
    "last_image_desc": "Remote control displays 27°C near an air conditioner.",
    "challenge": "Near-static",
    "caption": "Temperature setting on the remote increases from 21 to 27 degrees."
  },
  {
    "folder": "baby-duck",
    "first_image_desc": "Duckling swimming on water facing left with ripples behind.",
    "last_image_desc": "Duckling swimming left with beak open and ripples behind.",
    "challenge": "Large motion",
    "caption": "Duckling swims left and dips head into the water."
  },
  {
    "folder": "beach-ball",
    "first_image_desc": "Man with ball and dog near water, woman stands on sand.",
    "last_image_desc": "Woman holds ball on sand, man and dog near water's edge.",
    "challenge": "Large motion",
    "caption": "Woman catches ball thrown by man on the beach."
  },
  {
    "folder": "beach-metal",
    "first_image_desc": "Person with metal detector walking on sandy beach near ocean.",
    "last_image_desc": "Person stands on beach holding metal detector facing ocean waves.",
    "challenge": "Large motion",
    "caption": "Person walks forward on the beach with a metal detector."
  },
  {
    "folder": "bear",
    "first_image_desc": "A brown bear walks left among rocks and dirt.",
    "last_image_desc": "The brown bear steps forward with one paw raised on a rock.",
    "challenge": "Large motion",
    "caption": "The brown bear walks left and steps onto a rock."
  },
  {
    "folder": "bench-swing",
    "first_image_desc": "Empty wooden swing angled left between two posts outdoors.",
    "last_image_desc": "Empty wooden swing angled right between two posts outdoors.",
    "challenge": "Large motion",
    "caption": "Swing moves from left to right between the posts."
  },
  {
    "folder": "bird",
    "first_image_desc": "White cockatoo stands on a wooden perch with wings raised.",
    "last_image_desc": "White cockatoo sits on the perch with wings folded.",
    "challenge": "Large motion",
    "caption": "The white parrot repeatedly lowers and raises its body on the tree branch."
  },
  {
    "folder": "bird-tail",
    "first_image_desc": "A small brown bird stands on mossy wood with wings raised.",
    "last_image_desc": "The bird faces forward with wings flapping and tail upright.",
    "challenge": "Large motion",
    "caption": "Bird is dancing, flapping its wings and shaking its tail feathers."
  },
  {
    "folder": "bmx-bumps",
    "first_image_desc": "A person in motocross gear rides a bicycle on a dirt track.",
    "last_image_desc": "A person in dark gear obscures most of the view near the camera.",
    "challenge": "Occlusion",
    "caption": "The rider passes behind another person while cycling on bumpy terrain."
  },
  {
    "folder": "book",
    "first_image_desc": "An open book lies on sand with blank pages visible.",
    "last_image_desc": "An open book lies on sand with pages curled upward.",
    "challenge": "Large motion",
    "caption": "Book pages flip upward in the wind on the sand."
  },
  {
    "folder": "bowl",
    "first_image_desc": "Hand holds mallet above brass singing bowl in snowy forest.",
    "last_image_desc": "Hand holds mallet to the side of brass singing bowl.",
    "challenge": "Large motion",
    "caption": "Mallet circles counterclockwise around the rim of the singing bowl."
  },
  {
    "folder": "boxing-fisheye",
    "first_image_desc": "Two boxers with headgear face each other in a ring outdoors.",
    "last_image_desc": "Boxer in blue headgear lunges toward boxer in red headgear in ring.",
    "challenge": "Large motion",
    "caption": "Boxers are punching toward each other."
  },
  {
    "folder": "boy-bike",
    "first_image_desc": "A boy rides a bicycle on a rural road.",
    "last_image_desc": "The boy on the bicycle is much closer and smiling.",
    "challenge": "Linear motion",
    "caption": "A boy rides a bicycle toward the viewer."
  },
  {
    "folder": "breakdance",
    "first_image_desc": "Breakdancer balances upside down on one hand in front of crowd.",
    "last_image_desc": "Breakdancer lands on feet after spinning move in front of crowd.",
    "challenge": "Large motion",
    "caption": "Breakdancer spins from handstand to standing position on stage."
  },
  {
    "folder": "brown-sheep",
    "first_image_desc": "A brown goat stands on green grass facing left.",
    "last_image_desc": "A brown goat stands on green grass facing forward.",
    "challenge": "Large motion",
    "caption": "The goat walks slowly to the left, sniffing the scent of grass."
  },
  {
    "folder": "camel",
    "first_image_desc": "A camel stands near a wooden fence facing right.",
    "last_image_desc": "A camel walks away along the fence with another camel visible.",
    "challenge": "Occlusion",
    "caption": "A camel walks right as another camel appears behind it."
  },
  {
    "folder": "camel-white",
    "first_image_desc": "A white two-humped camel stands on grass facing right.",
    "last_image_desc": "The camel walks right with legs lifted and head forward.",
    "challenge": "Large motion",
    "caption": "A Bactrian camel walks right across the grassy enclosure."
  },
  {
    "folder": "cat-girl",
    "first_image_desc": "Girl holding a kitten close to her face outdoors.",
    "last_image_desc": "Girl smiling and holding kitten up in front of her face.",
    "challenge": "Large motion",
    "caption": "Girl lifts kitten upward in front of her face."
  },
  {
    "folder": "chamaleon",
    "first_image_desc": "A green chamaleon clings to a branch with legs extended.",
    "last_image_desc": "The green chamaleon has shifted forward along the branch.",
    "challenge": "Near-static",
    "caption": "A chamaleon is hanging from a branch."
  },
  {
    "folder": "color-run",
    "first_image_desc": "Hands with green powder approach people at a color run event.",
    "last_image_desc": "Hands move away revealing a runner in white shirt and orange powder.",
    "challenge": "Occlusion",
    "caption": "Hands with green powder move past runners at a color run."
  },
  {
    "folder": "cook",
    "first_image_desc": "Person holding knife and pointing at whole apple pie.",
    "last_image_desc": "Person places a slice of apple pie on a plate.",
    "challenge": "Large motion",
    "caption": "A slice of apple pie is served onto a plate."
  },
  {
    "folder": "cows",
    "first_image_desc": "Brown and white cow walking left on a dirt path.",
    "last_image_desc": "Brown and white cow farther left on the dirt path.",
    "challenge": "Linear motion",
    "caption": "Cow walks right along the dirt path."
  },
  {
    "folder": "dance-twirl",
    "first_image_desc": "A woman in a blue dress dances outdoors before a crowd.",
    "last_image_desc": "The woman in a blue dress raises her arm while dancing.",
    "challenge": "Large motion",
    "caption": "A woman in a blue dress performs a dance outdoors."
  },
  {
    "folder": "desert-camel",
    "first_image_desc": "Two people and two camels walking on sand at sunset.",
    "last_image_desc": "Two people and two camels further right on sand at sunset.",
    "challenge": "Linear motion",
    "caption": "Two people and two camels walk rightward across the desert."
  },
  {
    "folder": "dog-bark",
    "first_image_desc": "A Doberman with mouth closed looks upward on a leash.",
    "last_image_desc": "The Doberman has mouth closed and looks slightly to the side.",
    "challenge": "Large motion",
    "caption": "Doberman barks, showing its teeth."
  },
  {
    "folder": "dog-beach",
    "first_image_desc": "A black and brown dog runs on a sandy beach.",
    "last_image_desc": "The dog continues running on the beach with ears up.",
    "challenge": "Large motion",
    "caption": "The dog runs quickly to the left across the sandy beach."
  },
  {
    "folder": "dog-gooses",
    "first_image_desc": "A black and white dog crouches near a group of ducks on grass.",
    "last_image_desc": "The dog stands farther right as ducks move away on the grass.",
    "challenge": "Large motion",
    "caption": "The dog chases the ducks across the grassy field."
  },
  {
    "folder": "dog-snow",
    "first_image_desc": "Brown dog facing forward in falling snow.",
    "last_image_desc": "Brown dog looking to the left in falling snow.",
    "challenge": "Near-static",
    "caption": "Dog turns its head left in the snow."
  },
  {
    "folder": "dog-swim",
    "first_image_desc": "A golden retriever splashes in shallow water facing right.",
    "last_image_desc": "A golden retriever splashes in shallow water facing forward.",
    "challenge": "Large motion",
    "caption": "Dog runs through shallow water toward the viewer."
  },
  {
    "folder": "dog-water",
    "first_image_desc": "A black and white dog lies behind a white bowl indoors.",
    "last_image_desc": "The dog stands with its nose in the white bowl on the floor.",
    "challenge": "Large motion",
    "caption": "Dog walks forward and puts nose into the bowl."
  },
  {
    "folder": "dogs-scale",
    "first_image_desc": "A hand holds a small puppy near a kitchen scale on a table.",
    "last_image_desc": "A puppy sits on the scale while another puppy approaches the front.",
    "challenge": "Large motion",
    "caption": "A puppy is placed onto the kitchen scale."
  },
  {
    "folder": "drone",
    "first_image_desc": "Man holding phone stands by display of drones and gadgets.",
    "last_image_desc": "Man holds small white drone and phone near display counter.",
    "challenge": "Large motion",
    "caption": "Man picks up drone from floor and holds it up."
  },
  {
    "folder": "drum",
    "first_image_desc": "Man in headphones playing drums with right arm raised.",
    "last_image_desc": "Man in headphones playing drums with right arm lowered.",
    "challenge": "Large motion",
    "caption": "Drummer is passionately playing the drums."
  },
  {
    "folder": "four-walking",
    "first_image_desc": "Four women in white walk toward the camera on a cobblestone street.",
    "last_image_desc": "Four women in white close to the camera with legs in motion.",
    "challenge": "Large motion",
    "caption": "Four women in white walk forward on a cobblestone street."
  },
  {
    "folder": "frog",
    "first_image_desc": "A green frog sits on wet pebbles facing left.",
    "last_image_desc": "The same green frog sits on wet pebbles facing left.",
    "challenge": "Near-static",
    "caption": "The frog remains still on the wet pebbles."
  },
  {
    "folder": "gazelle",
    "first_image_desc": "A gazelle with horns is lying on sandy ground mouth slightly open.",
    "last_image_desc": "A gazelle with horns is lying on sandy ground mouth closed.",
    "challenge": "Near-static",
    "caption": "The gazelle is chewing something."
  },
  {
    "folder": "giant-slalom",
    "first_image_desc": "Skier in red suit skiing downhill past red flags on snow.",
    "last_image_desc": "Skier in red suit reappears on right side near blue flag.",
    "challenge": "Occlusion",
    "caption": "Skier disappears behind slope and reappears further right."
  },
  {
    "folder": "girl-dog",
    "first_image_desc": "Girl in wheelchair and dog moving along sidewalk near grass.",
    "last_image_desc": "Girl in wheelchair reaches out to dog sitting beside her.",
    "challenge": "Large motion",
    "caption": "Girl in wheelchair approaches and stops beside sitting dog."
  },
  {
    "folder": "girl-happy",
    "first_image_desc": "Woman in white shirt smiling with arms outstretched outdoors.",
    "last_image_desc": "Woman in white shirt smiling and facing left near green plants.",
    "challenge": "Large motion",
    "caption": "Woman turns left while smiling outdoors."
  },
  {
    "folder": "girl-music",
    "first_image_desc": "Person with closed eyes wearing headphones and touching both sides of head.",
    "last_image_desc": "Person with closed eyes wearing headphones and tilting head downward.",
    "challenge": "Large motion",
    "caption": "Person tilts head downward while listening with headphones."
  },
  {
    "folder": "girl-smile",
    "first_image_desc": "Girl in black jacket touches hair with both hands near her head.",
    "last_image_desc": "Girl in black jacket smiles with hands lowered and hair loose.",
    "challenge": "Large motion",
    "caption": "Girl lowers hands from head and smiles."
  },
  {
    "folder": "girl-turn",
    "first_image_desc": "Girl in yellow dress faces forward holding skirt.",
    "last_image_desc": "Girl in yellow dress faces left holding skirt.",
    "challenge": "Large motion",
    "caption": "Girl spins clockwise."
  },
  {
    "folder": "goat",
    "first_image_desc": "A goat stands on rocky terrain facing away.",
    "last_image_desc": "A goat stands on rocks facing right with head turned.",
    "challenge": "Large motion",
    "caption": "A goat steps right on rocky hillside."
  },
  {
    "folder": "goat-branch",
    "first_image_desc": "A brown goat walks under a large horizontal branch.",
    "last_image_desc": "The brown goat's head is further forward under the branch.",
    "challenge": "Large motion",
    "caption": "A goat is rubbing its back against a tree branch."
  },
  {
    "folder": "gorilla",
    "first_image_desc": "Adult and young gorilla sitting among green leaves.",
    "last_image_desc": "Adult and young gorilla sitting among green leaves.",
    "challenge": "Occlusion",
    "caption": "Young gorilla moves behind leaves beside adult gorilla."
  },
  {
    "folder": "gym-pull",
    "first_image_desc": "Man seated on gym machine with arms extended upward holding bar.",
    "last_image_desc": "Man seated on gym machine with arms extended upward holding bar.",
    "challenge": "Large motion",
    "caption": "Man performs lat pulldown exercise on gym machine."
  },
  {
    "folder": "gym-wave",
    "first_image_desc": "Man in white shirt swings battle ropes in gym.",
    "last_image_desc": "Man in white shirt swings battle ropes higher in gym.",
    "challenge": "Large motion",
    "caption": "A man swings a battle rope at the gym."
  },
  {
    "folder": "hike-man",
    "first_image_desc": "Person with backpack walking on a sunlit forest path.",
    "last_image_desc": "Person with backpack farther along the same sunlit forest path.",
    "challenge": "Linear motion",
    "caption": "A person walks forward along a forest path."
  },
  {
    "folder": "hoverboard",
    "first_image_desc": "Person standing on a hoverboard on a wet path near a railing.",
    "last_image_desc": "Person walking away from a hoverboard on a sloped path.",
    "challenge": "Large motion",
    "caption": "Person rides a hoverboard forward and then steps off."
  },
  {
    "folder": "india",
    "first_image_desc": "Several people walk and ride scooters on a sunlit street.",
    "last_image_desc": "A man in a plaid shirt blocks most of the view of the street.",
    "challenge": "Occlusion",
    "caption": "A man in plaid shirt moves in front of the street scene."
  },
  {
    "folder": "koala",
    "first_image_desc": "A koala climbs horizontally on a tree branch with head visible.",
    "last_image_desc": "A koala clings vertically behind a tree trunk with head mostly hidden.",
    "challenge": "Occlusion",
    "caption": "Koala climbs up and behind the tree trunk."
  },
  {
    "folder": "makeup",
    "first_image_desc": "Hand applies makeup brush to woman's closed eyelid.",
    "last_image_desc": "Hand holds makeup brush above woman's closed eyelid.",
    "challenge": "Large motion",
    "caption": "Makeup brush moves upward across eyelid."
  },
  {
    "folder": "man",
    "first_image_desc": "Man in blue shirt looking forward with neutral expression.",
    "last_image_desc": "Man in blue shirt with right eye partially closed and swollen.",
    "challenge": "Occlusion",
    "caption": "Man raises hand and rubs his right eye."
  },
  {
    "folder": "man-eat",
    "first_image_desc": "Man in glasses about to eat food with a spoon.",
    "last_image_desc": "Man in glasses chewing food with mouth closed.",
    "challenge": "Large motion",
    "caption": "Man eats food with a spoon and begins chewing."
  },
  {
    "folder": "monkeys-trees",
    "first_image_desc": "A monkey climbs a branch toward a tree in a grassy area.",
    "last_image_desc": "A monkey stands on the branches while another monkey is farther left.",
    "challenge": "Large motion",
    "caption": "Monkey climbs branches while another monkey jumps leftward."
  },
  {
    "folder": "paragliding-sky",
    "first_image_desc": "Paraglider with red canopy high above sea and mountains.",
    "last_image_desc": "Paraglider with red canopy moves leftward above sea and mountains.",
    "challenge": "Linear motion",
    "caption": "Paraglider drifts leftward through the sky above the sea."
  },
  {
    "folder": "parkour",
    "first_image_desc": "Man jumps over a metal barrier in an urban area.",
    "last_image_desc": "Man stands on a metal railing overlooking a street and greenery.",
    "challenge": "Large motion",
    "caption": "Man runs and vaults over barriers and railings outdoors."
  },
  {
    "folder": "rabbit-cute",
    "first_image_desc": "White and gray rabbit sitting in green grass facing forward.",
    "last_image_desc": "White and gray rabbit sitting in green grass facing left.",
    "challenge": "Large motion",
    "caption": "Rabbit turns head to the right."
  },
  {
    "folder": "rhino",
    "first_image_desc": "A rhinoceros stands on rocky ground near a tree and log.",
    "last_image_desc": "The rhinoceros is partially hidden behind a tree and facing left.",
    "challenge": "Occlusion",
    "caption": "A rhinoceros walks left and becomes hidden behind a tree."
  },
  {
    "folder": "rhino-dirt",
    "first_image_desc": "A rhinoceros stands on dirt facing right.",
    "last_image_desc": "A rhinoceros stands on dirt further right with lifted front leg.",
    "challenge": "Linear motion",
    "caption": "The rhinoceros steps forward on the dirt."
  },
  {
    "folder": "run-girl",
    "first_image_desc": "Girl in yellow shirt stands in wheat field at sunset.",
    "last_image_desc": "Girl in yellow shirt runs through wheat field at sunset.",
    "challenge": "Linear motion",
    "caption": "Girl runs forward through the wheat field."
  },
  {
    "folder": "salsa",
    "first_image_desc": "Dance group in sparkly outfits facing away from the audience.",
    "last_image_desc": "Dance group crouching in a circle with arms extended inward.",
    "challenge": "Large motion",
    "caption": "Dancers move from standing to crouching in a circle."
  },
  {
    "folder": "santa",
    "first_image_desc": "Man in Santa suit with headphones raises right hand near Christmas tree.",
    "last_image_desc": "Man in Santa suit with headphones lowers head and touches headphones.",
    "challenge": "Large motion",
    "caption": "Santa who is lost in the song, dances."
  },
  {
    "folder": "scooter-board",
    "first_image_desc": "Man rides a hoverkart toward the camera at a convention.",
    "last_image_desc": "Man on hoverkart reappears from behind a large black booth structure.",
    "challenge": "Occlusion",
    "caption": "Man on hoverkart circles around a large black booth structure."
  },
  {
    "folder": "soapbox",
    "first_image_desc": "Two people in a blue soapbox car approach a wooden ramp.",
    "last_image_desc": "Blue soapbox car has crossed the ramp with one person pushing behind.",
    "challenge": "Large motion",
    "caption": "Soapbox car rolls over the wooden ramp on the roadside."
  },
  {
    "folder": "soccer",
    "first_image_desc": "Person in gray sweatshirt balances soccer ball on foot outdoors.",
    "last_image_desc": "Person in black pants kicks soccer ball forward on paved ground.",
    "challenge": "Large motion",
    "caption": "Soccer ball is kicked upward by the person's foot."
  },
  {
    "folder": "squirrel",
    "first_image_desc": "A ground squirrel sits upright near a rock holding food.",
    "last_image_desc": "The ground squirrel sits upright with its paw raised to its mouth.",
    "challenge": "Near-static",
    "caption": "The rodent is eating its food."
  },
  {
    "folder": "stretch-girl",
    "first_image_desc": "Woman sits cross-legged on grass with hands resting on knees.",
    "last_image_desc": "Woman sits cross-legged on grass with arms raised overhead.",
    "challenge": "Large motion",
    "caption": "Woman extends her arms forward while sitting cross-legged on grass."
  },
  {
    "folder": "stroller",
    "first_image_desc": "Woman pushing stroller with child past shop window on cobblestone street.",
    "last_image_desc": "Woman and stroller have moved further right along the shop window.",
    "challenge": "Linear motion",
    "caption": "Woman pushes stroller with child to the right past shop window."
  },
  {
    "folder": "subway",
    "first_image_desc": "Several people walk past benches in a subway station.",
    "last_image_desc": "Two women stand near a pillar in the subway station.",
    "challenge": "Occlusion",
    "caption": "People walk past benches at the subway station."
  },
  {
    "folder": "sunset",
    "first_image_desc": "Sailboat on calm sea with large sun low in red sky.",
    "last_image_desc": "Sailboat farther right on sea with large sun higher in sky.",
    "challenge": "Linear motion",
    "caption": "Sailboat moves right across the sea at sunset."
  },
  {
    "folder": "sunset-girl",
    "first_image_desc": "Woman holding a light stands on the beach at sunset.",
    "last_image_desc": "Woman holding a light stands near a large rock at sunset.",
    "challenge": "Linear motion",
    "caption": "Woman walks along the beach holding a small light."
  },
  {
    "folder": "sunset-walk",
    "first_image_desc": "Person's legs entering from right on a path at sunset.",
    "last_image_desc": "Person walking away on a path toward the sunset.",
    "challenge": "Linear motion",
    "caption": "Person walks forward along the path toward the sunset."
  },
  {
    "folder": "sweep",
    "first_image_desc": "Broom sweeping debris toward red dustpan on wooden floor.",
    "last_image_desc": "Broom and dustpan on clean wooden floor with debris gone.",
    "challenge": "Large motion",
    "caption": "Broom sweeps debris into dustpan on wooden floor."
  },
  {
    "folder": "tiger-tree",
    "first_image_desc": "A tiger walks left past a large fallen tree.",
    "last_image_desc": "The tiger has moved further left with its mouth slightly open.",
    "challenge": "Large motion",
    "caption": "A tiger slowly walks to the right passing a fallen tree."
  },
  {
    "folder": "tractor-green",
    "first_image_desc": "A beige off-road truck is angled left near a dirt mound.",
    "last_image_desc": "The beige off-road truck is fully on flat ground facing left.",
    "challenge": "Large motion",
    "caption": "The off-road truck drives rightward onto the grassy field."
  },
  {
    "folder": "train-snow",
    "first_image_desc": "A train is distant on snowy tracks with falling snow.",
    "last_image_desc": "The train is much closer on the snowy tracks in heavy snow.",
    "challenge": "Large motion",
    "caption": "A freight train moves forward through heavy falling snow."
  },
  {
    "folder": "woman-cry",
    "first_image_desc": "Woman sitting on bed covering her face with hands. Man behind her.",
    "last_image_desc": "Woman sitting on bed covering her face with hands. Man behind her.",
    "challenge": "Near-static",
    "caption": "Woman sits on bed crying and covering her face with hands."
  },
  {
    "folder": "worry",
    "first_image_desc": "Man looking down with hand on chin in thought.",
    "last_image_desc": "Man looking up and to the side with hand on chin.",
    "challenge": "Large motion",
    "caption": "Man turns head upward while thinking."
  },
  {
    "folder": "writing",
    "first_image_desc": "Person in black shirt writes on paper beside laptop and yellow sleeve.",
    "last_image_desc": "Person in black shirt lifts pencil from paper beside laptop and yellow sleeve.",
    "challenge": "Large motion",
    "caption": "Person lifts pencil after writing on paper."
  }
]