Going Postal - Letter Box

Your task - to stuff a Letter Box with letters until it is completely full.  Oh! - and there are 2664 assemblies.  And you can’t just shove them in, some have to be rotated while they are in the box.  You may even find yourself stuck and frustrated if you’re not careful.

All the letters that you will be stuffing in Letter Box are copies of the L tromino - 9 of them.  They all have to be inserted through the small slot.  When solved, the 9 L trominos will completely fill the Letter Box.

Letter Box, designed by Pit Khiam Goh, was made by Cubicdissection and released in December 2020.  The box is made from Walnut and each of the L trominos is made from a different exotic wood: Wenge, Canxan, Jatoba, Zebra, Bloodwood, Purple Heart, Katalox, Chakte Viga, and Ash.  It’s especially nice that each of the L tromino pieces is made from a single piece of wood.  In addition to the slot that permits the L trominos to pass, there are 2 additional holes that can be used to view and manipulate the pieces within the box.

There are many ways to tackle a puzzle.  Since this puzzle has 2664 assemblies, I wouldn’t recommend an exhaustive approach to try each one until you find one that works.  Even if you found a working assembly, it may not be obvious since the solution requires rotating pieces within the box.  For this puzzle, a better approach would be to start at the other end and envision how the pieces would be removed from the box.  How would the first piece come out?  Then with the first piece out, how would the second piece come out?  Using this approach, I was able to find a workable assembly and determine the rotations needed to solve Letter Box.  Not overly difficult but a very nice challenge.