Three Key Box

This box is something of a puzzle. It requires three keys to open it!
The first key is in an Impossible Dovetail Box.
That key opens the second lock which is a tight screw and contains the second key.o
The second key turns the flipper to allow the slide lid of the third box to open. Inside is the final key which opens the main box!

For the whole process see the video at https://youtu.be/uowhm15nT7I

My Masonic brothers will notice that the keys are designed as Beauty, Wisdom and Streng