let xInc = 1, yInc = 1

let xDir = 1, yDir = 1

function setup() {

  createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  background(0);

  noStroke()

  fill(map(mouseX, 0, windowWidth, 0,255),map(mouseY, 0, windowHeight,0,255),255,205)

  ellipse(circleX,circleY,50)

  circleX = circleX+xInc*xDir

  circleY = circleY + yInc*yDir

  if (circleX>=windowWidth || circleY>=windowHeight){

    yDir = -1

    xDir = -1

    xInc = random(5)

    yInc = random(5)

  }

​

  if (circleX<=0 || circleY <=0){

    yDir = 1

    xDir = 1

    xInc = random(5)

    yInc = random(5)

  }

​

}

​

function mousePressed(){

  background(0)

  circleX = 0

  circleY = 0

}