Who wants a giant stone fist?
OK, it doesn't have to be stone. It could be wood, metal ... or living flesh! It might be a statue, or the hand of a petrified giant protruding from the floor, or an illusion, or even a permanent Bigby's Hand that has taken on a life of its own. It might be a magical trap, an object of worship, or a puzzle to solve. It might even contain something clutched within its grip. And although this image shows the fist rising from a dais, the circle on the geomorph might represent a pool or a pit.
The geomorph has one central room (the location of the fist) with a main door in the north and two secret doors along the sides. The three rooms in the east, south, and west are on a higher level and open onto a balcony overlooking the fist. A secret tunnel running under the eastern room connects the corridors that enter the east side of the geomorph.
Geomorph S6 might take a while, since the model I'm building as its central feature is a little more elaborate.