I want to send a laser cutter engineer an accurate image file so he can cut me 100 identical, tessellating shapes out of 4mm plywood. The problem is that the pattern I want to use is taken from an image found online of a hand drawn pencil piece by M.C Escher. The image you see below is beautiful but not mathematically perfect and if one of those fishes is cut out it will not tessellate 100% accurately. Is there brain enough and a program which can help to pull the lines slightly to create a perfectly tessellating fish? I'm sure there must be somewhere. I've tried myself but I don't have a clue, I've offered the puzzle to more technical-minded friends and they failed too. Anyone have any ideas, please?