# Lego® Sculptures :: Andrew Lipson

I love to make mathematical Lego® sculptures. They aren't constructed entirely without computer assistance; usually I write some C code to generate whatever the shape is and figure out which cells in a grid made up of 1x1x1 Lego® bricks should be filled in. The code outputs this as an LDraw .DAT file, separated into construction steps adding one complete layer of the structure in each step. Then I use MLCad to view the .DAT file. I play around with the parameters and repeat until I have something that looks nice and which will probably be able to balance. But that's the easy part. Now I have to try to construct it out of actual Lego® bricks so that it actually holds together.

Daniel Shiu and I worked on this as a joint project. There are no camera tricks, but the picture has to be taken from exactly the right place, and the final photograph was slightly distorted to emphasize the perspective effect. I'm especially pleased with the way the roof in the top left of the picture came out. See photos of the construction in progress. Lego® is a trademark of The Lego Group. On my website I post images of M.C. Escher's original works (C) Cordon Art, Baarn, the Netherlands on his website, used with permission, so that you may compare with the Lego® creations. All rights reserved.

Daniel Shiu and I worked on this as a joint project. We discovered a few nasty surprises that Escher had hidden in the picture (other than the obvious one). And we had to get the camera position just right for the picture to come out OK. The domes on top, and the slightly protruding cell wall at the near end of the bottom level, were both interesting exercises in half-brick spacing, and many of those useful 1x2 plate offset bricks with the single stud on top were used. We took a small liberty with the guy in the red hat at the bottom of the picture. In Escher's original, he's holding an "impossible cube", but in our version he's holding an impossible Lego® square. Well, OK, not quite impossible if you've got a decent pair of pliers (ouch). See photos of the construction in progress. Lego® is a trademark of The Lego Group. On my website I post images of M.C. Escher's original works (C) Cordon Art, Baarn, the Netherlands on his website, used with permission, so that you may compare with the Lego® creations. All rights reserved.

I think this is the most difficult single construction I have ever made out of Lego®. Those long sweeping curves, hanging unsupported in space... It's only when you get about 2/3 of the way up that you start to discover exactly which bits 1/3 of the way up aren't strong enough. And there are never enough 1x3 bricks... But I didn't cheat anywhere. The figure-eight knot has a nice tetrahedral skew-symmetry which the model illustrates quite well. On my website you can find more pictures and an LDRAW .DAT file generated by my program for this sculpture. Beware--the .DAT file builds it out of 1x1 bricks. Actually constructing this out of larger bricks so that it holds together is a (non-trivial) exercise! Lego® is a trademark of The Lego Group.

Daniel Shiu and I worked on this as a joint project. There are no camera tricks, but the picture has to be taken from exactly the right place, and that was a challenge in itself. Unlike many of Escher's other "impossible" pictures (like "Ascending and Descending"), there is actually no optical illusion involved here. Gravity seems to be working in three different directions simultaneously, but the picture shows a perfectly self-consistent physical scene. So modelling it should certainly be feasible. But while Escher's picture has three different "up"s, Lego® isn't quite so flexible. See photos of the construction in progress. Lego® is a trademark of The Lego Group. On my website I post images of M.C. Escher's original works (C) Cordon Art, Baarn, the Netherlands on his website, used with permission, so that you may compare with the Lego® creations. All rights reserved.

This is a nice example of a saddle point. The model shows (most of) one cell of a doubly-periodic Scherk surface. Actually Scherk discovered more than one minimal surface in 1835, but this one has the particularly simple parametrisation given by $\exp(z) = \cos(x)/\cos(y)$. This model shows the surface in the region $|x|, |y| < p/2 - 0.01$. As with most of my mathematical surfaces, I made use of some computer assistance. On my website you can find more pictures and an LDRAW.DAT file generated by my program for this sculpture. Beware--the .DAT file builds it out of 1x1 bricks. Actually constructing this out of larger bricks so that it holds together is a (non-trivial) exercise! Lego® is a trademark of The Lego Group.