Having read a printed D&D adventure in one of my newer sourcebooks, I found within a small riddle encounter area. Riddles and puzzles haven't been used enough, but since I'm not good at guaging how difficult said riddle is, I thought I might present it to the blogosphere before deciding whether I should use it or not...

So here goes... see if you can work out the solution.

You have been led to an ancient crypt due to a strange artifact that you recovered: A jade obelisk the size of a dagger.
You stand in a 45 x 20 foot rectangular chamber, having entered from a door to the south. Along the north wall are two exits; one towards the west end of the wall, and one towards the east. Both of these archways are barred by a powerful forcefield.
The stretch of wall between the two archways is covered with a grand mosaic depicting a mountainside with two cave entrances, there is also a message written in the tiles (more on that in a second).

In the centre of the chamber, an ornate three-layered fountain bubbles noisily as water cascades down it. Around the bottom layer of the fountain are carvings of orcs. Around the middle layer are carvings of ogres in battle. At the top layer, four gargoyle heads (coloured red, white, green and blue) are carved into the stone, each with opened mouths into which something can be placed. Topping the fountain is a large upright hammer made of gold.

So now to the message in the mosaic:

Look here to find the middle,
Look here to answer the riddle.
Green stone in a gargoyle's mouth,
The safest route is to the south.
But should you wish to travel on,
Place the key in monster's yawn.
One path is safe, three mouths lie,
Every one will help you die.
Which colour do I like the best?
That's the answer to this test.

And below, the riddle:

I love high, but hate heights,
Best is better than good.
The colour that I like
Is neither tree nor fire, nor grave.
It more resembles a map or chart,
But never a globe.

What are you going to do?