Let’s make an animation.

Define some variables as follows.

val sizeOfLamp = 250
val redLamp    = circle(sizeOfLamp, Red)
val yellowLamp = circle(sizeOfLamp, Yellow)
val greenLamp  = circle(sizeOfLamp, Green)
val trafficLights = Buffer(redLamp, yellowLamp, greenLamp)

Package o1 provides an effectful function animate that displays a number of images one after another, thus turning them into an animation. The function expects two parameters:

• a bufferful of pictures; and

• a positive number (Double), that determines the speed of the animation. A larger number results in a faster animation.

Experiment with animate. In the field below, enter a command that animates the contents of the buffer that the variable trafficLights refers to. Use the speed 1.0. If you want, go ahead and come up with other things to animate.