Solid Pentominoes Two Layer - Wooden Brain Teaser Puzzle

Some of the oldest poly form wooden puzzles first formed as chessboards. Here in the two layer version.
The Solid Pentominoes contain 12 pieces; each consisting of five squares joined edge to edge forming different shapes.
You may find the shapes of the alphabet letters:I,L,P,T,U,V,W,,Y,Z. the F looks like it had an accident and N takes some imagination.
The Solid Pentominoes offer great challenges to the puzzler, For example: Try build a rectangle size 6x10 - This rectangle has 2339 different solutions. A 3x20 rectangle has only 2 solutions. A 4x15 rectangle has 368 solutions. A 5x12 rectangle has 1010 solutions. A 5x4x3 cube has 3940 solutions. A 6x5x2 cube has 264 solutions. A 10x3x2 cube has 12 solutions. This brain teaser puzzle comes complete with a box and a lid so that the pieces can be stored away for safe keeping. If you think building blocks is kid's stuff, try to build this square (as well as many other shapes).
The Solid Pentominoes are called planar because all shapes lie in one plane.