Doom 3 Easter Egg - Familiar Images from Hell

In certain parts of Doom 3, there's a rather large demonic glyph written on the floor.

This is not to be confused with small ones which occasionally pop up when an enemy is teleporting in. I am referring to a very large glyph I remember seeing in Hell.

Here's a picture.

http://home.comcast.net/~chrismb/pentastic1.jpg

At around 7 o'clock, assuming the northmost point on the map is 12 o'clock, there's the original Doom Marine face, grinning. He is easiest to see when making a southwest line from the north-east most pentagram point, as the image is slightly tilted.

Slightly north-east of the Doom Marine face is a very small UAC logo, circa Doom1/2.