Patented by F. G. Dustin 1935
this one made by Diniar Namdarian 2013; sleeve made by J. A. Storer.
(Laser cut plastic, 4.75" x 4.75" x 1/4";
base is 1/8" thick, tray edge is 1/8", thick and pieces are 1/8" thick)
Looks like the
puzzle at first,
until you notice that pieces,
except for piece 15, are joined together in pairs.
Described on page 151 of
who notes that are a number of ways to solve it.
The designer has made the pieces sufficiently tight so that solution is possible but not via Figure 4 shown in the Dustin patent:
from: www.uspto.gov - patent no. 1,993,211