My Sketch

var fillStyle=0;

var alph=0;

var inc =0;

var xv=10;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(100);

  smooth();

  frameRate(60);

​

​

}

​

function draw() {

  background(200);

  checkerboard(-60,-60);

  push();

​

  translate(width/2,height/2);

  rotate(TWO_PI/360*inc);

  checkerboard(-width/2-80,-height/2-80);

  pop();

  inc+=1;

}

  function checkerboard(xx,yy){

    var xv=20;//map(mouseX,0,width,10,20);

    var yv=15;//map(mouseY,0,height,10,20);

 for(var i = xx;i<width+35;i+=xv){  //Set up a nested loop for the rows & columns

    for(var j =yy;j<height+35;j+=xv){

      fill(fillStyle,alph);  //Set the fill color to be the color stored in fillStyle

      rect(i,j,xv,xv); //Draw the square

      if(fillStyle==0){  //Switch the fill color variable after drawing each square

        fillStyle=255;

        alph=0;

      } 

      else{

        fillStyle=0;

        alph=255;}

    }

​

  if((i+j)%2==0 && fillStyle==0){

    fillStyle=255;

    alph=0;}

  else if((i+j)%2==0 && fillStyle==255){

    fillStyle=0;

    alph=255;}

 }

  }