​

function setup() {

  createCanvas(400, 400);

​

  //square(0,0,100)

  //square(100,0,100)

  //square(200,0,100)

  //square(300,0,100)

  //blockSize = constrain(mouseX,4,width);

  for (let y=0; y < height; y+=blockSize){

  for (let x=0; x<width; x+=blockSize){

    fill(random(255),random(255),random(255))

    square(x,y,blockSize)

  }

}

}