Once upon a time there was a DM that spent too much time thinking about AD&D instead of playing it. Because of this, he concocted more and more puzzly things to spring on players. And when the chance arose to play, lo did he give them a room with 6 magical puzzle doors and the player were sore bored.
Centuries later he decided that perhaps someone could use these doors in their megadungeon, though he advises strongly against more than one door per level! Here is door the first:
It is inscribed in Professor Tolkien's Elvish and the inscriptions mean:
I don't claim that this is grammatically correct (elves are known to be lax with their grammar). These were basically three snippets of poetry by a single Elvish author dealing with grass, and a clump of fresh grass presented to it opened it. All that work and there was an elf in the party who read the door and opened it with no work at all :)