Possible answser for http://wouter.coekaerts.be/2012/puzzle-clowns

You.java

package you;

import clowns.Clown;
import clowns.Volkswagen;

public class You {

	private static class BandOfClowns extends Clown {

		final int id;
		final Volkswagen vw;

		public BandOfClowns(int id, Volkswagen vw) {
			System.out.println("One more clown, I'm #" + id);
			this.id = id;
			this.vw = vw;
		}

		public int hashCode() {
			if (id != 1) {
				vw.add(new BandOfClowns(id - 1, vw));
			}
			return super.hashCode();
		}
	}

	public static void main(String args[]) {
		Volkswagen vw = new Volkswagen();
		vw.add(new BandOfClowns(20, vw));
		vw.done();
	}
}