Cell grid in p5.js

gridcell.js

var app = (function () {
  
      var a2 = {
        'make' : (x,y) => { return { 'w' : x, 'v' : Array.from({length:x*y}, () => Math.random() * 255) } },
        'get' : (a, x, y) => { return a.v[x+y*a.w] },
        'set' : (a, x, y, v) => { a.v[x+y*a.w] = v }
      };

      var a;
      return {
        'setup' : () => {
          createCanvas(400, 400);
          a = a2.make(20,20)
        },
        'draw' : () => {
            background(220);
            var x = 400.0 / 20.0;
            var y = 400.0 / 20.0;
            for(var i = 0; i < 20; i++) {
              for(var j = 0; j < 20; j++) {
                fill(a2.get(a, i, j))
                a2.set(a, 10,10, Math.random() * 255)
                 square(i * x, j * y, 20)   
              }  
            }
        }        
      } 
    })();


function setup() {
  app.setup()
}


function draw() {
  app.draw()
}