Lego Soma

According to Thorleif Bundgaard's "The official history of SOMA" the soma cube came about in Denmark in the 1930s. I was introduced to the concept via Martin Gardner's "More Mathematical Puzzles and Diversions", and my grandfather helped me make my first Soma cube when I was a teenager (sadly, the glue wasn't all that strong and it fell apart after a little while.)

One of my other passions in life is Lego, and so when I noticed that my current cube was slightly warped, I pondered making another cube, this time from Lego. I researched a whole bunch of neat sites on the net:

However, I'm a pretty avid fan of schleim/SNOT technique, and a quick search found a useful hint from Dan Sabath / Bram Lambrecht about embedding tiles or mini-slopes in the bottom of a brick to act as semi-studs for inverted tiles.

I ended up having just enough black pieces in my existing collection to put together a set of soma pieces using these techniques. I grabbed a load of 1/1 tiles from the Creator set number 4956, to use for the internal connections - while the slopes work well for a 2x2 brick, they're not so useful on the 2x4 bricks that I ended up using. Also, there's actually a couple of kinds of connection on the bottom of the brick, one is pretty solid but the other has thinner walls with a ridge to hold the stud, and doesn't hold the tiles so well. In the end, I didn't have enough 2x4 bricks of the right type, so I combined 2x2 brick with technic pin, which did have the right grip, with 1x2 brick with axle hole and another 1x2 brick.

Here's the assembled cube, front and back (I turned it upside-down for the "back" shot, so you can see all 6 faces):

Front of Soma Cube

Back of Soma Cube

And here's the pieces separated out:

Pieces of Soma Cube

It's really nice to have the tiles all facing outwards, rather than having the bottoms of the pieces showing. Actually building anything with the pieces can be a little tricky though, as they tend to slip about a bit. Well, wouldn't want it to be easy now...