{
  "stage":
  {
    "left":   0,
    "right":  0,
    "top":    0,
    "bottom": 0
  },

  "ball":
  {
    "r":     75,
    "x":     75,
    "y":     75,
    "vx":   300,
    "vy":  -400,
    "ax":     0,
    "ay":   400
  }
}