This week's geomorphs in the B series involve fallen columns that block exits. Geomorph B6 has a central hall of Grecian-style columns, with one that has fallen against a door. Since the columns are 5 feet in diameter, climbing over them and out the 6-foot tall door is going to be difficult, if not impossible. There's also a pair of rooms on a slightly lower level, one with a corner that intrudes below the hall.
Also included are two endpieces with narrower hallways. EB3 is a simple row of four columns, one of which has fallen to block a doorway. The corridor outside the far door has a secret passage heading east.
EB4 has a double row of five columns each, one row supporting a gallery that isn't reachable from inside the room unless the explorers want to climb. The east end of the gallery has stairs down to a doorway that leads east.