#MechanicalEngineers: How would one do a box with slots for two "keys" where one of them *must* always stay inserted?

I need something like this for a (door) key management system:

You want a key? Fine, you can only take it if you insert your name tag to unlock the key. When you put the ky back, you get your name tag back.

The inserts would preferrably need to be without too sharp corners for pocket-friendlyness

#askfedi #3Dprinting #3Ddesign

Referenced link: https://techxplore.com/news/2023-06-mechanical-fresh-insight-battery-based-desalination.html
Discuss on https://discu.eu/q/https://techxplore.com/news/2023-06-mechanical-fresh-insight-battery-based-desalination.html

Originally posted by Phys.org / @physorg_com: http://nitter.platypush.tech/TechXplore_com/status/1666543187404439557#m

RT by @physorg_com: #Mechanicalengineers lend fresh insight into battery-based #desalination technology @UofIllinois https://hcvalidate.perfdrive.com/fb803c746e9148689b3984a31fccd902// https://techxplore.com/news/2023-06-mechanical-fresh-insight-battery-based-desalination.html

Referenced link: https://techxplore.com/news/2023-03-mechanical-explore-kitchen-3d.html
Discuss on https://discu.eu/q/https://techxplore.com/news/2023-03-mechanical-explore-kitchen-3d.html

Originally posted by Phys.org / @physorg_com: http://nitter.platypush.tech/TechXplore_com/status/1638208863882149889#m

RT by @physorg_com: #Mechanicalengineers explore kitchen uses for 3D #printing @CUSEAS https://techxplore.com/news/2023-03-mechanical-explore-kitchen-3d.html

CuriousMarc over here fearlessly repairing a 1960's vintage #IBM mechanical keyboard from the era when #MechanicalEngineers ruled the world.

https://youtu.be/ZWLptl0cKSc