ArchPort also has tennis shoes with secret compartments in the soles. I tried to find more information on these, but the ArchPort site is not very intuitive.
Homework Table, part of the collection “Self Discipline” by Nik Zupanc, has a mechanism that allows you to open a secret folded space to store paperwork, supplies, etc.
The video is tilted sideways, but this secret bookcase door slides straight back into a small room. They use some type of hanger/slides at the top of the bookcase. This gives me some ideas.
