window.onload = function() {

  var canvas = document.getElementById("canvas"),

      context = canvas.getContext("2d"),

      width = canvas.width = 600,

      height = canvas.height = 600;

  context.lineCap = "round";

  context.lineJoin = "miter";

  context.miterLimit = 1;

  context.lineWidth = 20;

  context.strokeStyle = "#999999";

  draw();

  context.lineWidth = 1;

  context.strokeStyle = "#ff0000";

  draw();

  function draw() {

    context.beginPath();

    context.moveTo(50, 50);

    context.lineTo(150, 50);

    context.stroke();

    context.beginPath();

    context.rect(200, 200, 100, 100);

    context.stroke();

    context.beginPath();

    context.moveTo(390, 500);

    context.lineTo(400, 400);

    context.lineTo(410, 500);

    context.stroke();

  }

};