Cyraxpt: OH GOD, TO HELL WITH THIS THREAD. Really? I have a vague memory of it, i remember that last fight with the boss on the lava but why would i have such a memory of those symbols (runes)? I was pretty sure it was something that i've wrote down to pass something... Sigh, i end up always disappointed with the answer...
Anyway, i don't have talent for drawing and somehow, even missing, i prefer to guess so i'll give my turn to someone with better drawing skills than me.
LOL!
Well, (not to talk down to you) Quake had 4 episodes and a central Hub you started in a large open room and chose a hallway to select your difficulty. the next room you entered was a square room with 4 hallways. Each hallway led to a portal into each episode. Unfortunately, only 2 bosses exist in the game. Chthon at the end of episode 1, which gave you the first rune after you electrocuted him, and Shub-Niggurath at the end of the final game. You reached him by collecting the runes in each Episode. once that is done, it takes you back to the main room, and the floor will have been opened to a pit with the portal to the final boss.
But, the game was also released as Shareware, only including the Hub level and the first Episode... maybe you only played that.