[jvmboi]

One unstated rule is that you have to use all pieces. Number three can already be solved with two pieces and that also doesn't count. I strongly dislike this kind of puzzle.

[matthewfelgate]

Thanks for sharing. Where does it even say you need to use every piece?!

[crtasm]

An unstated rule: not said/stated.

[maupin]

It doesn't say it. It probably should.