A fun little puzzle using 10 x 1 Cent coins (EUR). Try and place the 10 coins inside the square. 

Changes over the original:

adjusted tolerances

adjusted the border of the Tray to make it equally thick on all sides

removed the embossed Text

modified the spare Coin holder to make removal easier

Tolerance for the spare coin is quite tight (so that it doesn't fall out on its own). If too tight scale the model up by a small amount.

I have attached a solution as pdf to avoid image preview (the puzzle is fairly simple though) 

as always think outside the box and have fun ;)