Rainbow Wave

int num = 20;

float step, sz, offSet, theta, angle;

​

void setup() {

  size(1112, 834);

  colorMode(HSB, 255);

  strokeWeight(22);

  step = 45;

  background(255);

}

​

void draw() {

  background(255);

  translate(width/2, height*.75);

  angle=0;

  for (int i=0; i<num; i++) {

    stroke(255-i/num*255, 200, 255);

    noFill();

    sz = i*step;

    float offSet = TWO_PI/num*i;

    float arcEnd = map(sin(theta+offSet),-1,1, PI, TWO_PI);

    arc(0, 0, sz, sz, PI, arcEnd);

  }

  resetMatrix();

  theta += .03;

}