Some time ago I wanted to build a Soma cube with LEGO. There were some pictures in the net, but all of the cubes had monochrome pieces. What I wanted was the typical checkered cube. So I had to build one myself. :-)
About this creation
With black and white 4-wide cubes it's no problem, you just connect them in the middle. But with 2-wide cubes you need some tricks to connect them. Thanks to TLG we have 2x1 Technic bricks with 2 holes now, which can be connected with connector pegs. And in the corners I used 1x1 Technic bricks with a hole on the outside and 2x2 corner bricks on the inside.
Completed with 2x2 plates and tiles the pieces look nice and smooth. The pieces are not mounted in the position they will be in the solved puzzle by two reasons: 1st I didn't want to make the solution too easy and 2nd I wanted to build them in the easiest way. So in each piece I put as many cubes as possible one on top of the next one and used the desribed bricks to connect the rest.
By the way: Today I googled again and found 2 Soma Cubes apperently built the same way I did it: One built by Topsy Cret and one by Jeremy Moody. Damn, I wasn't the only one with this idea :-))
So, the next thing to do is obviously to buy the pieces missing to build it. I think, I will combine it with the slide puzzle and order a nice box at LEGO DESIGNbyME :-)