How to build the impossible

This past Friday we spent the afternoon at Explora Museum. The kids had a good time, played at the water table, spent loads of time at the sounds exhibit, exploring different musical instruments, and time in the building blocks area. I only got one picture to share.

Actually, Andy took this picture with his cell phone and I managed to transfer it here.




He built this with Kapla blocks, having watched a museum volunteer build a similar one.

Andy started with two arches, each made from two vertical blocks with a horizontal span. Each additional layer of horizontal blocks is placed just slightly interior, until they almost meet in the middle. Add several layers of blocks to bridge the space, and the outer vertical blocks as columns to counter-balance the center stack. Once that's all in place, the outside columns can be carefully removed, leaving this impossible-looking archway.

The two blocks on top, leaning to center are Andy's design flair, and not structurally necessary.