For thousands of years, if you wanted to send a secret message, there was basically one way to do it. You’d scramble the message using a special rule, known only to you and your intended audience.

The original version of this story appeared in Quanta Magazine. For thousands of years, if you wanted to send a secret message, there was basically one way to do it. You’d scramble the message using a ...

This video compares two LEGO safes a key lock safe and a combination lock safe both built using standard LEGO bricks. The tutorial explains how each locking system works, how the internal mechanisms ...