​

function setup() {

  createCanvas(400, 400);

}

​

​

  //blockSize = constrain(mouseX,10,150)

  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)

    }

 }

​