A fun and challenging puzzle. It is not easy as seen. There are a few ways the solve this. Even if you try to keep the solution in mind, you will not succeed. That's why I'm adding the solution below :) Also, you can print the solution guide.
All the pieces fit together perfectly. If the parts force each other, check your bed setting.
You can print the parts one by one in different colors or all of them in one color. All STL files added.
If you like my design, please write a comment and share your print with everyone :)
The author hasn't provided the model origin yet.