Hi everyone! Here’s something you can make. This is a puzzle cube made from post-it notes. It’s actually called a Soma cube. It’s quite famous amongst mathematicians. It’s made from seven pieces–a bit like Tetris pieces, and they fit together to make a cube. There are actually 240 solutions to the Soma cube, and yeah, you can make these yourself. So this origami Soma cube, I did make from post-it notes, and you actually need 122 post-it notes to make this, and you fold them into these things. These are called Sonobe units, and then these fit together to make cube shapes, which are perfect for these puzzle pieces. If you don’t know already, I’ll link to a separate video which explains how to make these Sonobe units. But first, let’s have a look at the shape of each piece. The first two pieces are the V piece and the L piece, named for obvious reasons. The V piece is made from 14 Sonobe units, while the L piece, and all other puzzle pieces, are made from 18 Sonobe units each. The next two pieces are the Zed piece and the T piece. When you’re making these puzzle pieces, have a look at where the inside edges are, and where the outside edges are. The next two pieces are mirror images, so we’ll call them A and B–and notice, we have now gone three dimensional. And the final and seventh piece is the pyramid piece, so we’ll call this P for pyramid. Those are all the pieces, and if you make them correctly, they will fit together to make a Soma cube. So this is quite a challenge. It took me eight hours to complete my first cube. To begin with, I wasn’t that good at it. An estate agent would probably describe it as having a “rustic charm.” But I did get better at it as I went along. So then I decided to make a second Soma cube with origami paper, and this came out a little bit neater. It fits together a bit better. But it is quite an achievement if you can make one. It is something that you can display. I should say “Thank you” to my mathematical friend Allison Kiddle, who taught me how to do this, so thank you, Allison! And you can follow her on Twitter. I hope you try it. Good luck with it! And if you have been, thanks for watching.