let canvas = createCanvas(600, 600);

}

​

function draw() {

background(255);

  fill(150,40,40)

  circle(mouseX,mouseY,60);

 for (let i=0; i<=width; i+=40) {

    line(i,0,width-i,height);

 }

  for (let j = 30; j < height; j += 30) {

    line(0, j, width, height - j);

  }

  if (mouseX > 300 && mouseY > 300)

    stroke('blue');

  else if (mouseX > 300 && mouseY < 300)

    stroke('red');

  else if (mouseX < 300 && mouseY > 300)

    stroke('yellow');

  else if (mouseX < 300 && mouseY < 300)

    stroke('green');

}