Inspired by this video:
I set about recreating this amazing Japanese large-beam wood joint. This is a roughly 12" x 6" beam, and it has a few subtle features such as small angles on the ends to make it easy to wedge together or apart, but it should be fairly faithful to the video shown.
I wouldn't recommend printing this out, it's quite large! But it could be used as a guide, or printed in miniature.