This is it….. your goal is to put 16 pennies (mint pennies provided with puzzle) into the quadrant sized opening. There is one unique solution and the pennies will just fit. They use 74.7% of the available area. Good luck finding it quickly… I think 20 minutes would be an excellent solution time.
Packing puzzles are an interesting branch of mathematics which you may want to check more into if you are so inclined.