console 命令行工具 X clear

console

function draw() {
    var ctx = document.getElementById('canvas').getContext('2d');
    ctx.translate(75, 75);

    for (var i = 1; i < 6; i++) { 
        ctx.save();
        ctx.fillStyle = 'rgb(' + (51 * i) + ',' + (255 - 51 * i) + ',255)';

        for (var j = 0; j < i * 6; j++) {
            ctx.rotate(Math.PI * 2 / (i * 6));
            ctx.beginPath();
            ctx.arc(0, i * 12.5, 5, 0, Math.PI * 2, true);
            ctx.fill();
        }

        ctx.restore();
    }
}

<html>
 <body onload="draw();">
   <canvas id="canvas" width="300" height="300"></canvas>
 </body>
</html>