Sometimes describing how a lock actually works can be the hardest part of teaching someone about lockpicking. [Mike Gee] has designed an acrylic lock that may just be the ticket for these situations. All of the pieces are cut from clear acrylic. As you insert the key, you can see it raise the four pins up to the shear line. He says that it will definitely take some tweaking as you assemble it to get it to function smoothly. Embedded below is a video of the lock in use. You can find plans on Thingiverse.