This is my partner R’s house, next to my studio; we worked on it between roughly 2006 and 2011.
Originally there was a small bungalow here; when the opportunity to buy it came up, we first considered extending and modifying it, much as R had done with her previous house a few miles away  -   a house which had all kinds of archaeological layers and interesting details. The bungalow unfortunately did not have all kinds (or indeed any kinds) of archaeological layers or interesting details; it needed a lot of work doing just to stand still, and it soon became obvious that the only sensible option was to start again.
R stumbled on an interesting kernel of an idea online, involving a central hexagonal open-plan room with bedroom wings; the original was a wooden holiday cabin, but the arrangement lent itself to being rethought as a proper house. We soon thrashed out the basic design, but it became apparent that architects tended to want something around £20,000 just to draw it up. Hmm, I thought to myself, £20,000?!   Let’s spend a few hundred on some architectural software and I’ll see if I can figure out what to do with it.
TurboCad (Mac version) turned out not too difficult; on the left are some of the resulting drawings and some photos of the result, which resembles the drawings gratifyingly.
Our excellent structural engineer recommended an all-round ring of steels, supported on corner posts, with glue-lam beams for the roof; the progress of the build is fairly obvious from the photos.
The whole project has been satisfying in outcome, though of course occasionally fraught.  I'm sure all the details will be finished one day...