Heinrich Q Wikepedistein delineates two separate Cavemen theatre set cultures, the Freiwandern and the Hohleblieb. Hohleblieb was based on the cave as a sacred location. The show was developed to fit the specific constraints of the cave. Fire and lamplight were used used from a variety of different angles, and the shapeshifting of shadows cast by stalactites was a major attraction at many caves … If you went to a play at Lé Creux ès Fées, you knew you were going to see a dude turn into a tiger at some point in the show.
In a museum setting, these performers would find a way to reflect or deflect light from any source. The projector would be the very best light, and only the Alpha Caveman got to reflect or deflect the projector light (according to Wikepedistein, the Alpha Caveman was usually a woman). If they found cleaning products containing fluorescent dyes, those would definitely be used for set painting.
Freiwandern was the roadshow. As the theatre of the caveless it is replete with underdog trickster themes. Setpieces were lightweight and collapsible for a nomadic lifestyle, a lot of stick and sinew tensegrity structures and umbrella-like handhelds. For a complex show a performer may carry a quiver of umbrellas. Use of local materials served as a crowd-pleasing shout-out to the audience: in this case the performer has used the museum’s supply of powdered wigs to rig some extravagant pants…