공 튀기기
int x=250;int y=250;int speed=3;
void setup() { size(500,500);}
void draw() { background(0); ellipseMode(CENTER); ellipse(x,y,50,50); if(x>500 || x<0) speed=-speed; x=x+speed; if(y>490 || y<0) speed=-speed; y=y+speed; }
