fullscreen float r = 0;
void setup() {
size(400, 400);
background(10);
smooth();
noStroke();
frameRate(1000);
colorMode(HSB);
}
void draw() {
fill(r%255,255,255);
rotate(r);
ellipse(100+r, 0, 10, 10);
fill(255-r,255,255);
ellipse(90+r, 10, 10, 10);
r += 0.2;
}
Experimenting with ellipses, rotation, and HSB color I got this.