コッホ曲線完成 - ツナドーナツ・技術メモ帳

<!DOCTYPE html>
<html lang="ja">
<head>
<title>コッホ曲線を描く</title>
<meta charset="UTF-8">
<style>
#canvas {
background: #FFFFFF;
}
</style>
</head>
<body>
<canvas id="canvas" width="640" height="480"></canvas>
<input type="button" value="start" onclick="drawLoopSquare();"/>
<script>
function drawLoopSquare() {
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext('2d');
var width = canvas.width;
var height = canvas.height;
var x = 1.0;
var y = 0.0;
var plusX = 0.0;
var plusY = 0.0;
var size = 2;

//描画フロー
function render() {

/*1番目の時*/
if(rand() == 1) {
plusX = 0.5 * x + (Math.sqrt(3) / 6.0) * y;
plusY = (Math.sqrt(3) / 6.0) * x - 0.5 * y;
x = plusX;
y = plusY;
console.log("x:", x, "y:", y);

ctx.beginPath();
ctx.fillRect(x * 640, 450 - (y * 480), size, size);

/*2番目の時*/
} else if(rand() == 2) {
plusX = 0.5 * x - (Math.sqrt(3) / 6.0) * y + 0.5;
plusY = -(Math.sqrt(3) / 6.0) * x - 0.5 * y + Math.sqrt(3) / 6.0;
x = plusX;
y = plusY;
console.log("x:", x, "y:", y);

ctx.beginPath();
ctx.fillRect(x * 640, 450 - (y * 480), size, size);
}
}

for(var i = 0;i < 6000;i++) {
render();
}
/*ランダム関数*/
function rand(){
var r;
r = Math.floor(Math.random() * 2) + 1;
return r;
console.log("random:", r);
}
}
drawLoopSquare();
</script>
</body>
</html>
実行結果：
書き方変かもしれないけど初心者だしゆるして