Hard problems are great because once you solve them, you get to solve even more challenging things as a result. I (with a small and great group of people) build a lot of physical things that are meant to look deceptively simple through various means, mostly being the disappearance of artefact of support. This leads to a lot of great design, engineering, documentation, and procurement logistic challenges. Past: wrapping a building in custom made chain-mail and need it to a) fit like a glove, b) not fall off, and c) not cause us to go broke. Current: 18,000m2 (196k SF) of entirely custom, double curved aluminium panels. The unique part count is currently hovering around 1,000,000 distinct components that all need to end up on a piece of paper (the building industry is big, slow, and strange).