from mcpi.minecraft import Minecraft
mc = Minecraft.create()
x,y,z = mc.player.getPos()
base = 10
height = base//2+1
for i in range(height):
    x1 = x+i
    y1 = y+i
    z1 = z+i
    x2 = x+base-i
    z2 = z+base-i
    mc.setBlocks(x1,y1,z1,x2,y1,z2,41)