This is a very simple extension that shows an image of a key.  There are four teeth, each with four letters. The players can click on any tooth to slide it up or down, forming different 4-letter words.  

The DM can select which teeth are visible (in case you want your players to find each part separately).

In this version, the letters are hard-coded, but MANY words are possible.  It wouldn't be hard to make the letters configurable (or the font, if you want runes instead).