//5-9 simple gravity, a square falls from the top of the screen and bounces

float x = 100;
float y = 0;

float speed = 0;
float gravity= 0.1;

void setup () {
  size (200, 200);
}

void draw () {
  background (255);

//display the square
 fill(0);
 noStroke();
 rectMode(CENTER);
 rect(x,y,10,10);
 
 y= y + speed;
 
 speed = speed + gravity;
 
 //If square reaches the bottom
 //Reverse speed
 if (y > height) {
   speed = speed * -0.95;
 }
}