Why Boundary - well it looks like a 6 piece burr, but is actually on a 4 piece burr.
In cricket a Boundary can be a 6 or a 4 depending if the ball bounces before crossing the Boundary.
So it could be a 6 but is only a 4 :)
Revenge of the Minotaur
TRi Again 2
A revised version with pieces that pass all the way through the opposite piece. Designed to help print on 3d printer.
Big Burred 71 flat
3Piece Burr Cube
12 pieces based on a 3 piece burr, make this box that requires 75 or 80 moves to take apart