js生成玫瑰，0依赖，代码如下

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
		<style>
      html,body{
      	width: 100%;
      	height: 100%;
        margin: 0;
        border: none;
        padding: 0;
        background-color: rgba(255, 255, 1, 0.2);
      }
      #app{
      	width: 100%;
      	height: 100%;
      	display: flex;
        justify-content: center;
        overflow: auto;
      }
    </style>
	</head>
	<body>
		<div id="app" >
      <div id="app-main" style="width: 300px;height: 700px;"></div>
    </div>
	</body>
	<script>
    (function() {
    	var dom = document.getElementById("app-main")
    	dom.offsetWidth
    	var canvas = document.createElement('canvas');
    	//将创建的画布添加至right dom当中
    	var context = canvas.getContext('2d');
    	dom.appendChild(canvas)
    	var zBuffer = [];
    	var SIZE = 700;
    	var h = -280;
    	
    	function surface(a, b, c) {
    		var A = a * 2 - 1;
    		var B = b * 2 - 1;
    	
    		//茎
    		if (c > 60) {
    			return {
    				x: Math.sin(a * 7) * (13 + 5 / (.2 + Math.pow(b * 4, 4))) - Math.sin(b) * 50,
    				y: b * SIZE + 50,
    				z: 625 + Math.cos(a * 7) * (13 + 5 / (.2 + Math.pow(b * 4, 4))) + b * 400,
    				r: a * 1 - b / 2,
    				g: a
    			};
    		} else if (A * A + B * B < 1) {
    			if (c < 32) {
    				//花瓣
    				var o = A * (2 - b) * (80 - c * 2);
    				var w = 99 - Math.cos(A) * 120 - Math.cos(b) * (-h - c * 4.9) + Math.cos(Math.pow(1 - b, 7)) * 50 + c *
    				2;
    				var z = o * Math.sin(c) + w * Math.cos(c) + 700;
    				return {
    					x: o * Math.cos(c) - w * Math.sin(c),
    					y: B * 99 - Math.cos(Math.pow(b, 7)) * 50 - c / 3 - z / 1.35 + 450,
    					z: z,
    					r: (1 - b / 1.2) * .9 + a * .1,
    					g: Math.pow((1 - b), 20) / 4 + .05
    				};
    			} else if (c < 37) {
    				//小叶
    				c = c * 1.16 - .15;
    				var o = a * 45 - 20;
    				var w = b * b * h;
    				var z = o * Math.sin(c) + w * Math.cos(c) + 620;
    				return {
    					x: o * Math.cos(c) - w * Math.sin(c),
    					y: 28 + Math.cos(B * .5) * 99 - b * b * b * 60 - z / 2 - h,
    					z: z,
    					r: (b * b * .3 + Math.pow((1 - (A * A)), 7) * .15 + .3) * b,
    					g: b * .7
    				};
    			} else {
    				//叶子
    				var j = c & 1;
    				var n = j ? 6 : 3.55;
    				var o = .5 / (a + .01) + Math.cos(b * 125) * 3 - a * 300;
    				var w = b * h;
    				return {
    					x: o * Math.cos(n) + w * Math.sin(n) + j * 610 - 390,
    					y: o * Math.sin(n) - w * Math.cos(n) + 550 - j * 350,
    					z: 1180 + Math.cos(B + A) * 99 - j * 300,
    					r: .4 - a * .1 + Math.pow(1 - B * B, -h * 6) * .15 - a * b * .4 + Math.cos(a + b) / 5 + Math.pow(Math
    						.cos((o * (a + 1) + (B > 0 ? w : -w)) / 25), 30) * .1 * (1 - B * B),
    					g: o / 1e3 + .7 - o * w * 3e-6
    				};
    			}
    		}
    	}
    	var intime= null
    	function initRosa(){
    		canvas.width=dom.offsetWidth
    		canvas.height=dom.offsetWidth
    		// canvas.height=dom.offsetHeight
    		intime= setInterval(function() {
    			for (var i = 0; i < 10000; i++) {
    				var part = i % 46;
    				var c = part / .74;
    				var point = surface(Math.random(), Math.random(), c);
    				if (point) {
    					var z = point.z;
    					var x = parseInt(point.x * SIZE / z - h);
    					var y = parseInt(point.y * SIZE / z - h);
    					var zBufferIndex = y * SIZE + x;
    					if ((typeof zBuffer[zBufferIndex] === "undefined") || (zBuffer[zBufferIndex] > z)) {
    						zBuffer[zBufferIndex] = z;
    						var r = -parseInt(point.r * h);
    						var g = -parseInt(point.g * h);
    						var b = -parseInt(point.r * point.r * -80);
    						context.fillStyle = "rgb(" + r + "," + g + "," + b + ")";
    						context.fillRect(x*(dom.offsetWidth/SIZE), y*(dom.offsetWidth/SIZE), 1, 1);
    					}
    				}
    			}
    		}, 0);
    		setTimeout(function(){
    			clearInterval(intime)
    		},1000 * 190)
    	}
    	window.addEventListener('resize',function(){
    		clearInterval(intime)
    		context.clearRect(0,0,context.width,context.height);  
    		initRosa()
    	})
    	initRosa()
    })()
  </script>
</html>