Entered into the design competition in Narita, Japan, August 2013.
This puzzle is made out of Trespa which is a pressed wood material.
The object of this puzzle seems easy enough. Just remove the coin. There are metal balls that will stop you from getting the coin out. Take your time when trying to solve this puzzle. The solution will come to you.
Due to this being a handmade puzzle, there may be imperfections. The solution of the puzzle is still the same.