104

float y = 50.0;
float radius = 15.0;
float velocity = 0.0;
float acceleration = 0.01;

void setup(){
size(100,100);
smooth();
noStroke();
ellipseMode(RADIUS);
}


void draw(){
fill(0,10);
rect(0,0,width,height);
fill(255);
ellipse(33,y,radius,radius);
velocity += acceleration;
y += velocity;
if(y >height+radius){
y = -radius;
}
}