Pentomino Puzzle

The goal of this puzzle is to fit all the pieces inside the 6 x 10 base. There are 12 unique pieces and each piece is made up of 5 square units. You can rotate and flip the pieces however you want. There are 2339 solutions to this puzzle (I put the number on the base so I wouldn't forget it). The lid has a solution so that you can always fit all the pieces in to put the lid on.To print you can use the file with all the pieces or print each one individually if you want to make it more colorful. You can also try and fit them in a 5x12 area (1010 solutions), 4 x 15 area (368 solutions), or 3 x 20 area (2 solutions).

Update 3/24/20:
I have updated the lid to make it easier to print. "Lid v2.stl" is the new version and the old version is still available.