To the north is a triangle of dull ecru
stone, outlined with some sort of gray
metal; a throbbing radiance seems to
spread in dun-colored pulses that wash
over the area. 

To the east is a great 10'
square of translucent stone, blue at the
edges and shading to a deep green at the 
center, bordered by a strip of pale green;
the whole gives out undulating sheets of
blue-green light. 

To the south is a circle
of translucent crystal ringed by a silvery
band; the whole sends forth slowly rising
clouds of pale light, that spread and disappear. 

To the west is a long diamond
shape with four points radiating from the sides of the lozenge. 
The whole is fashioned of translucent stone mottled red
and amber, outlined in red gold. It sends
up sudden tongues of brightness, planes
of pale fiery light that vanish as quickly
as they appear.

All of these radiations gleam from the
walls and floor of the hall. Any object in
the center of the four symbols shows the
four different illuminations, and the
ghastly purple of their mix. If you look
upward long enough, occasional glints
of light can be seen from the vaulted ceiling, that peaks 60' or more overhead.
The 30' wide aisle to the west appears to
be the only entrance to the place.