GUIbyP5.java

import processing.core.*;
public class GUIbyp5 extends PApplet{
    public static void main(String[] args) {
    }

    public void settings() {
        size(640, 480);
    }

    public void setup() {
        colorMode(HSB, 100);
        background(0);
    }

    public void draw() {
        noStroke();
        rectMode(CORNER);
        fill(0, 5);
        rect(0, 0, width, height);
        rectMode(CENTER);
        fill(random(100), 60, 100);
        rect(random(width), random(height), 40, 40);
    }
}