Wonder Puzzle 25 by Mitsuhiro Odawara

Puzzle description:
Wonder Puzzle 25 looks like an easy polyomino puzzle, but it has an additional magic twist: Here, the polyominoes consist of rectangles instead of squares. 
First problem: Put the four polyominoes into the tray so that they form a 4x6 rectangle. Only one solution.
Second promblem: You have an additional small rectangle. Now fit all six pieces into the same tray! Again, only one solution.

This wonder puzzle was designed by Mitshiro Odawara in 2013 (https://torito.jp/puzzles/hako068.shtml) and is presented here with his kind permission.

If you can read German: Mehr Informationen gibt es in https://welt-der-geduldspiele.blogspot.com/search?q=3D-Druck

Puzzle difficulty: 
The first problem is relatively easy, and the large clearance is essential for problem 2.
The second problem is difficult until you find out where the additional space comes from.

Printing instructions:
Prints are fine with no supports. 
I printed the puzzle in PLA at 0.1 mm layer height.
The STL files were generated using PuzzleCAD: https://www.thingiverse.com/thing:3198014.