context.setStrokeStyle(canvasGradient);
context.beginPath();
context.moveTo(0 , canvasHeight/3);
context.lineTo(canvasWidth*2/3, canvasHeight/3);
context.lineTo(canvasWidth*2/3, 0);
context.lineTo(canvasWidth, canvasHeight/2);
context.lineTo(canvasWidth*2/3, canvasHeight);
context.lineTo(canvasWidth*2/3, canvasHeight*2/3);
context.lineTo(0, canvasHeight*2/3);
context.lineTo(0, canvasHeight/3);