Panefull Puzzle – Window Packing

You will go through great panes to solve this puzzle.  Four of them to be exact.

Window Packing was designed by Koichi Miura and exchanged in this year’s International Puzzle Party (IPP) by Meiko Kimura.  The puzzle is made from laser-cut acrylic and consists of a window frame and 4 blue tetromino pieces (1-I, 1-Z, 2-L) that need to be packed into the frame.  The 2 outer layers of the frame are made with gray frosted acrylic and have 4 large openings that come in handy to manipulate the pieces within the frame.  The center layer is clear and made from 2 pieces, but I have to confess that I don’t know why it isn’t a single piece.  

You will immediately notice that the O-penings on the front of the puzzle are not the same shape as the pieces to be packed inside.  Hint -  One corner of the middle layer has a single voxel opening (2 sides) to allow the pieces to be inserted within the frame.

This puzzle is not difficult, but it’s not trivial either.  It does require the rotation of pieces within the frame.  However, it should be obvious which piece needs to go in last and that doesn’t leave too many assemblies to check.  The rotations required to get the pieces in position are not difficult and the large openings help accomplish this.
 
I found packing this window frame much more enjoyable than packing the window frame in my old storm door for the winter.  Window Packing is a good entry puzzle for 2D packing.