a demonstration of me folding this flagstone tessellation: https://flic.kr/p/wv6ji5
it shows me keeping on folding after the steps of this photo tutorial: https://flic.kr/s/aHskgPmmVR
specifically it shows how I clean up the border of the model.
although I discovered the folding sequence on my own the pattern was reverese-engineered from a photo by Peter Keller who in turn saw this structure in a model by Joel Cooper
