gistfile1.txt

void setup() {

  size(602, 400);

  ellipse(50, 50, 60, 60);
}

float xPosition = 100f;
float yPosition = 100f;
int t = 0;
float vX = 3;
float vY = 3;
boolean enteredFrame = true;
float g = 2;

// x(t) = x0 + v * t;
void draw() {
  background(255);

  vY =(g + vY);

  xPosition = xPosition + vX;
  yPosition = yPosition + vY;

  yPosition = Math.max(30f, yPosition);
  yPosition = Math.min(height - 10f, yPosition);
  
  ellipse(xPosition, yPosition, 60, 60);

  if (xPosition + 30 > width || xPosition - 30 < 0 ) {
     vX = vX * -1;
  }

  if (yPosition + 30 > height || yPosition - 30 < 0) {
    //noLoop();
      vY = vY * -1;
      vY = vY / 1.15f;
    }
}