Rectangles: (4 entries)
  0: Rectangle: x1=0, y1=0, x2=20, y2=30
  1: Rectangle: x1=40, y1=50, x2=75, y2=75
  2: Rectangle: x1=70, y1=90, x2=115, y2=112
  3: Rectangle: x1=125, y1=115, x2=150, y2=150