Reflected Code

This puzzle starts with a printed series of digits that could potentially be used with a combination lock.

This code, however, does not open any lock. The trick is that players have to use a mirror to see the reflection of the digits. The reflected image has the correct code.

When selecting numbers for the code, make sure that each digit makes sense in both the original printing and in the mirror image. For example, the reflection of 7 does not form a digit, so you cannot use that one.

Likewise, make sure the font used for the digits reflect well. For example, the digits 2 and 5 can make nice reflections of each other, but many fonts have enough asymmetry to make the reflection not resemble the digit well. For the example above, I drew the digits myself to make sure they reflected well. Drawing digits using a seven-segment display template works well.

When setting up this puzzle, consider mounting the code on a wall (with instructions for players to not remove it from the wall). Because you are using digits that reflect well, they will also look correct upside down. Problems with orientation can be avoided if the code is mounted on a wall in a fixed orientation. To make the puzzle more interesting, consider also mounting the mirror on an opposite wall so players have to orient themselves to get the code reflected in the mirror.