Protect yourself from enemy agents.
There's no better place to hide things out of plain sight than a book safe!
Encode and decode secret messages.
Create a portable, wearable symbolic map. Should you be captured by an enemy agent – the map will be unreadable by them – only you will know the meaning of the symbols on your secret map.
Create sunglasses that allow you to have “eyes in the back of your head” so you are aware of your surroundings when completing top secret missions.
Build a signaling device to “tag” a moving car, mark a dead drop site location, or send a signal from a rooftop at night.
Keep your secrets safe!