Intelligence Box

I found this very old wooden jigsaw puzzle version, but I don't know who should be credited for its original design.

Goal:Put all six components into the box.

Difficulty:It's challenging—this intelligence box requires time and patience.

There's no need to force it. If you have to force it, it means you're going the wrong way.

You can reduce it by up to 50%, and the tolerance will still apply.

The solution is included in the document.

Hint 

Have you ever tried to rotate a component?