This is a hexagonal impossible dovetail demonstration piece that should be printed in 2 colors for maximum effect.a 0.1mm tolerance gap was included to allow for a secure, but not too tight fit.

I'd recommend a 50% infill to give the fins some strength. As it is the thin fins on part 1 are not that strong and won't be able to handle much abuse. to add strength to to these fins, it may be worth trying to print this part on it's side so that the grain of the print goes up and down the fin and not across it. You could also scale it larger than I made it to give the base of this fin a larger area , though it would take longer to print. Your call.