效果图：
方法一：
复制代码代码如下:<!DOCTYPE HTML>
<html>
<body>
<canvas id=”myCanvas” width=”500″ height=”500″>your browser does not support the canvas tag</canvas>
[removed]
var deg = 0;
var r = 30;
var rl = 100;
function drawTaiji() {
var canvas = document.getEl
