new_contents: import numpy as np
  import matplotlib.pyplot as plt
  
  xs = np.fromfile('utcs.dat', dtype=np.uint32)
  ys = np.fromfile('values.dat', dtype=np.uint64)
  
  print('Loaded')
  
  xs = np.random.choice(xs, size=1000000)
  ys = np.random.choice(ys, size=1000000) / 1e8
  xmin = xs.min()
  ymin = ys.min()
  xmax = xs.max()
  ymax = ys.max()
  
  print('Sampled')
  
  plt.scatter(xs, ys, cmap=plt.cm.YlOrRd_r)
  plt.axis([xmin, xmax, ymin, ymax])
  plt.title('Bitcoin Balances Over Time')
  
  print('Ready')
  
  plt.show()
  
subject: add heatmap example w/ balances over time