This is perhaps the most difficult puzzle that I've ever designed. I specifically wanted to find something that mixed and matched pieces from the TernCode Burr (orange) and SuperCode Burr (red) and so used BurrTools to run some computer analysis on a bunch of variations. The conclusion of this analysis showed me that the longest solution path would include the two custom white tab insert pieces. I've never even tried to solve this puzzle on my own (without following along the computer output solution path) but have met a few puzzlers who've told me that they can solve this without help, and said that they really enjoyed it. Hats off to them!