canvasGradient.addColorStop(1, "rgba(200,20,120, 1)");
context.setFillStyle(canvasGradient);
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);