Just like in the Da Vinci Code. It works much like a bicycle combination lock and if one arranges the rings to spell out the correct password, the rings align to unlock it, and the entire cylinder slides apart. In the inner compartment of the cryptex, this is where secret information can be hidden.

This was sorta a school project. For an engineering project we had to invent something.

Step 1: Materials

-(2) 2" PVC end caps
-(1) 1.5" PVC coupler
-(1) 1.5" PVC tubing (about 7")
-(1) 2" PVC tubing (about 7")
-(3) .5" x 5" x .125" clear acrylic strips
-Dremel Tool
-Superglue

Step 2: Cutting

Cut the 2" PVC tubing into:
-(2) 2 1/8" pieces
-(5) 3/4" pieces

Step 3: Sanding

Sand down the insides of the 2" PVC rings and also the inside/outside of the coupler, until it fits snuggly inside the 2" PVC ring. Do this 4 more times. Then cut a 1/2" notch in the 1 1/2" coupler, then glue to the inside of the 2" PVC ring.

Step 4: Glue and Cut

Glue one of the 2 1/8" piece of the 2" PVC into the end cap, glue the 1 1/2" PVC to the other end cap. Then slide the 2" piece into the end cap but DO NOT glue.

Cut a 2 1/4" x 1/2" piece of PVC, then glue it onto the 1 1/2" PVC tube

Step 5: Password

Next you must decide what you want your password to be, then put the letters of the word you chose above the notch, then complete the rest of the alphabet on the ring, then slide the rings onto the 1 1/2" PVC tube.

But also make sure that you can create a riddle or something with your password. Mine was PIANO, and the riddle was.. i am a box that holds keys without locks, but can unlock your soul. What am i?

Step 6: Finishing Touches

Just Put the other end cap on and glue on the acrylic strips. But only glue them onto the 2" PVC pieces that are in the end caps. And there you go, a cryptex!