I often whip up little areas I imagine and scrap them quickly, but today I had this image of an octagonal point room, with the 2 direct doorways descending into the point from indoors, and 2 side doors ascending to the point, and it got away from me. By hour 2 I had this.
Hour 3 I had a small playtest with a friend and found some bugs and some things I'd like to change, took a break to play some tf2 with friends and have dinner, came back and 5 hours total later..