100 spirals (2025)

// make source code public

// schien@mail.ncku.edu.tw, Spring 2025

//

// 100 spirals with random starting/ending/stepping controls

// program for lectures on "The Wrong Way to Draw a Circle"

// schien@mail.ncku.edu.tw

// Fall 2018

//

// adjusted for let/var differenciation (prefer let scoping)

// schien@mail.ncku.edu.tw, Spring 2023

//

​

function setup() {

  createCanvas(500, 300);

  noLoop();

​

}

​

function draw() {

  background(255);

  strokeWeight(0.5);

  noFill();

  let radius;

  let centerX = width/2;

  let centerY = height/2

  stroke(0, 30);

  for (let i=0; i<100; i++) {

    let x, y, rad=0; 

    let nextX, nextY, nextR=0;

    radius = 10;

    let radiusNoise = random(10);

    let startAngle = random(360);                                   

    let endAngle =  1440 + random(1440);                            

    let angleStep =  5 + random(3);

    for (let ang=startAngle; ang<endAngle; ang+=angleStep) { 

      radius += 0.5;

      radiusNoise += 0.05;

      let thisR = radius + noise(radiusNoise)*200 - 100;

      if (nextR === rad) {

        rad = radians(ang);

        x = centerX + thisR * cos(rad);

        y = centerY + thisR * sin(rad);

      }

      nextR = radians(ang+5);

      nextX = centerX + thisR*cos(nextR);

      nextY = centerY + thisR*sin(nextR);

      line(x, y, nextX, nextY);

      x = nextX;

      y = nextY;

    }

  }

}