Don't be mistaken. This is not about one of the most evil men in modern history, but rather the name of Rik van Grol's IPP35 Exchange Puzzle in Ottawa, Canada. Before anyone has anything to comment about the choice of name, here's Rik's explanation in his notes accompanying the puzzle:-
1. "Bin", which is short for "binary", refers to the solution method.
2. "Laden" is Dutch for drawer or tray
3. "Bin Laden" is the name of someone considered by many as the personification of the the devil. In a "devilish" streak, I took the liberty to ignore the "rules" of a true binary puzzle
4. "Too" sounds like "two" and means my second Bin Laden puzzle is equally "devilish"
(NB: Rik had designed the first Bin Laden puzzle for his exchange in Boston in 2006, reviewed by Oli Sovary-Soos here)
First off, the BLT is long and rectangular and entirely laser cut and glued together from layers of wood. It measures about 16.5cm x 5.5cm x 4.5cm. It's a secret opening box with 5 small drawers or trays. Standing vertically, it looks like a miniature cabinet with short legs to boot.
The object of the BLT is to "remove all five dice from their trays and close all the trays again". As Rik has mentioned in his notes, he has deviated away from a true binary puzzle design. For those in the dark about binary and such, check out Goetz Schwandtner's article on binary/n'ary puzzles.
I have played with a number of n'ary type puzzles before such as Cross & Crown 2013, Numlock and Schloss 250 so I kinda knew what to expect and how to go about solving. Simply put, there is a repeated sequence of moves that have to be made to arrive at the final solution. The challenge is to firstly discover that sequence AND then to remember it; one misstep and you are almost always guaranteed to go back to square one....in fact you might get stuck and not even able to start from beginning again.
Solving consist of pulling and pushing the individual drawers in and out of the box. The top and bottom panels are also able to move upwards and downwards (about 0.4cm) within certain limits and these affect the movements of the drawers. So in total you got 7 moving pieces (with mechanisms all hidden from view) to navigate inside the box.
I started off noting down on paper the early moves and at first there appeared to be some tangible sequence but after about nine moves, the sequence went out the window. What happened the next 45 mins or so was more trial and error trying to get the drawers opened. Each of the drawers do not either fully extend or retract but rather have various stop positions which adds to the difficulty. Proper alignment is also crucial, otherwise you might miss a move on one of the drawers. One by one I managed to get all the 5 dice out, but with a lot of effort. And thereafter in my attempt to repeat the moves, I got mixed up and it was another trial and error session before I managed to finally close all the drawers, and re-open them again. However, I just couldn't get the lowest drawer to open fully like I did the first time, so I was not able to return the 5th dice to it.
I will have to ask Rik for the solution or wait until the IPP35 Exchange Puzzle Booklet is out to find out how to solve the BLT in the fewest moves possible. Like Rik had pointed out, this isn't a true binary puzzle so as far as I could tell, there was no "repeated sequence" to be found and the puzzle behaved just like a burr, only thing is that the BLT's moves are hidden inside the box.
For a trick opening box, this is a great concept with the use of drawers and a "pseudo-binary" design to ensure a large number of moves to fully solve the puzzle. But the BLT is anything but short of very challenging and certainly something very different from the usual high level burrs.