I have always loved these types of puzzles, ring puzzles, box puzzles, ball puzzles. Each year my family would give me a bunch of them for xmas/birthday/etc. 10-15 new puzzles each year some are pretty complex but i have never seen anything as complicated as Lee Krasnow’s Barcode Burr.
With so many possible ways to notch the pieces (each of which would yield a different puzzle solving experience) Lee Krasnow decided to design the notches of the Barcode Burr so that the pieces moved in a binary progression. This means that when all six pieces are retracted, the first move is to extend piece #1 which will then allow piece #2 to extend. Once #2 is extended, #1 must be pushed back in before #3 may extend. Because #3 is extended, #4 is now able to move, but not until #2 gets pushed back in place. Of course #2 cannot move until #1 is extended again, and then once this happens #1 must be pushed back in before #4 can finally move.
I didn’t see a price tag on the Barcode Burr but I expect it to be pretty damn expensive.