var Fibonacci = [];

function setup(){
 createCanvas(windowWidth, windowHeight);//创建一块画板，画板的宽高与浏览器宽高相同
 background(255);//设置背景颜色为白色
 frameRate(10);//设置每秒10帧
}

function draw(){
 ...
 stroke(0);//线条颜色为黑色
 noFill();//无填充色
 strokeWeight(5);//线条宽度为5
 translate(windowWidth/2, windowHeight/2);//将坐标系移动到页面中央
 ...
}

function draw(){
 ...
 stroke(0);
 noFill();
 strokeWeight(5);
 translate(windowWidth/2, windowHeight/2);
 ...
 for( var i = 0; i < 20; i ++){//绘制20段90度弧线
  var a = i <= 1 ? 1 : Fibonacci[i-1] + Fibonacci[i-2];
//这是条件表达式，如果i等于0或1，那么a等于1；否则等于斐波那契数列前两项的和
  Fibonacci.push(a);//将新得到的a加入斐波那契数列中
  arc(0,0,a * 2,a * 2,0,PI / 2);//绘制圆心在(0,0)直径为2*a度数为90度的弧形

  /**********以下是为下一段弧线做准备************/
  rotate(PI / 2);//将坐标系按顺时针旋转90度
  translate(-Fibonacci[i-1],0); //将坐标系沿着X轴反向移动上一项的长度
 } 
}

function draw(){
 background(255);//将背景设置成白色，“遮盖”之前的绘图
 stroke(0);
 noFill();
 strokeWeight(5);
 translate(windowWidth/2, windowHeight/2);
 rotate(-PI / 6 * frameCount);//每帧旋转30度，frameCount表示当前已播放帧数
 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);
}