Removing the Mystery of Euler's Formula [PDF]
An explanation of Euler's Formula (e^ix = cos x + i sin x). [Mirrored from my temporary website]
Storing messages in playing cards
How to encode and encrypt binary data into a deck of 52 playing cards.
Things from years ago:
How to remember which cards have been dealt from a pack of cards: here
Dismantling a Chubb Manifoil combination lock: here