p5.js使用draw()函數做出黃金螺旋

var Fibonacci = [];

function setup(){
 createCanvas(windowWidth, windowHeight);//創建一塊畫板，畫板的寬高與瀏覽器寬高相同
 background(255);//設置背景顏色為白色
 frameRate(10);//設置每秒10幀
}

function draw(){
 ...
 stroke(0);//線條顏色為黑色
 noFill();//無填充色
 strokeWeight(5);//線條寬度為5
 translate(windowWidth/2, windowHeight/2);//將坐標系移動到頁面中央
 ...
}

function draw(){
 ...
 stroke(0);
 noFill();
 strokeWeight(5);
 translate(windowWidth/2, windowHeight/2);
 ...
 for( var i = 0; i < 20; i ++){//繪制20段90度弧線
 var a = i <= 1 ? 1 : Fibonacci[i-1] + Fibonacci[i-2];
//這是條件表達式，如果i等于0或1，那么a等于1；否則等于斐波那契數列前兩項的和
 Fibonacci.push(a);//將新得到的a加入斐波那契數列中
 arc(0,0,a * 2,a * 2,0,PI / 2);//繪制圓心在(0,0)直徑為2*a度數為90度的弧形
 /**********以下是為下一段弧線做準備************/
 rotate(PI / 2);//將坐標系按順時針旋轉90度
 translate(-Fibonacci[i-1],0); //將坐標系沿著X軸反向移動上一項的長度
 } 
}

function draw(){
 background(255);//將背景設置成白色，“遮蓋”之前的繪圖
 stroke(0);
 noFill();
 strokeWeight(5);
 translate(windowWidth/2, windowHeight/2);
 rotate(-PI / 6 * frameCount);//每幀旋轉30度，frameCount表示當前已播放幀數
 for( var i = 0; i < 20; i ++){
 var a = i <= 1 ? 1 : Fibonacci[i-1] + Fibonacci[i-2];
 Fibonacci.push(a);
 arc(0,0,a * 2,a * 2,0,PI / 2);
 rotate(PI / 2);
 translate(-Fibonacci[i-1],0); 
 } 
}

var Fibonacci = [];
function setup(){
 createCanvas(windowWidth, windowHeight);
 background(255);
 frameRate(10);
}
function draw(){
 background(255);
 stroke(0);
 noFill();
 strokeWeight(5);
 translate(windowWidth/2, windowHeight/2);
 rotate(-PI / 6 * frameCount);
 for( var i = 0; i < 20; i ++){
 var a = i <= 1 ? 1 : Fibonacci[i-1] + Fibonacci[i-2];
 Fibonacci.push(a);
 arc(0,0,a * 2,a * 2,0,PI / 2);
 rotate(PI / 2);
 translate(-Fibonacci[i-1],0); 
 } 
}
function windowResized(){
 resizeCanvas(windowWidth, windowHeight);
}