While I was in Billund, I visited Loplet, a flea market renowned for having vintage LEGO for sale. I picked up some Modulex, which was first released in 1963 as a building tool for architects. After sorting what I had bought, I discovered some beautiful Modulex tiles. After a bit of fiddling around to get the placement geometry right, I was able to build Modulex Heights, a modern office block with wonderful feature panels on two sides.