var ctx = document.getElementById('tutorial').getContext('2d');

  ctx.strokeStyle = "#fc0";

  ctx.lineWidth = 1.5;

  ctx.fillRect(0,0,300,300);

  // Uniform scaling

  ctx.save()

  ctx.translate(50,50);

  drawSpirograph(ctx,22,6,5);  // no scaling

  ctx.translate(100,0);

  ctx.scale(0.75,0.75);

  drawSpirograph(ctx,22,6,5);

  ctx.translate(133.333,0);

  ctx.scale(0.75,0.75);

  drawSpirograph(ctx,22,6,5);

  ctx.restore();

  // Non uniform scaling (y direction)

  ctx.strokeStyle = "#0cf";

  ctx.save()

  ctx.translate(50,150);

  ctx.scale(1,0.75);

  drawSpirograph(ctx,22,6,5);

  ctx.translate(100,0);

  ctx.scale(1,0.75);

  drawSpirograph(ctx,22,6,5);

  ctx.translate(100,0);

  ctx.scale(1,0.75);

  drawSpirograph(ctx,22,6,5);

  ctx.restore();

  // Non uniform scaling (x direction)

  ctx.strokeStyle = "#cf0";

  ctx.save()

  ctx.translate(50,250);

  ctx.scale(0.75,1);

  drawSpirograph(ctx,22,6,5);

  ctx.translate(133.333,0);

  ctx.scale(0.75,1);

  drawSpirograph(ctx,22,6,5);

  ctx.translate(177.777,0);

  ctx.scale(0.75,1);

  drawSpirograph(ctx,22,6,5);

  ctx.restore();

function drawSpirograph(ctx,R,r,O){

  var x1 = R-O;

  var y1 = 0;

  var i  = 1;

  ctx.beginPath();

  ctx.moveTo(x1,y1);

  do {

    if (i>20000) break;

    var x2 = (R+r)*Math.cos(i*Math.PI/72) - (r+O)*Math.cos(((R+r)/r)*(i*Math.PI/72))

    var y2 = (R+r)*Math.sin(i*Math.PI/72) - (r+O)*Math.sin(((R+r)/r)*(i*Math.PI/72))

    ctx.lineTo(x2,y2);

    x1 = x2;

    y1 = y2;

    i++;

  } while (x2 != R-O && y2 != 0 );

  ctx.stroke();

}