​

function setup() {

  createCanvas(400, 400);

}

​

​

​

​

​

​

function draw() {

  //background(220);

}

​

 function mousePressed(){

   background(255);

  //if i clikc on left

   if (mouseX < 200){

     //then do this

     //fill with black

     fill(0);

     //recatngle on left side

     rect(0,0,200,400)

   }

   //make left black

   if (mouseX > 200) {

     fill(0);

     rect(200,0,200,400);

   }

   //if i click right 

   //make right black

}