Here is one idea I'm working on to increase the amount of models I can display by building upwards, as my shelf is quite high between each one. Currently WIP, but currently I can fit 6 more stands than I would on the shelf without the structure.
The setting is that Tyranids have invested a mountain and created a network of tunnels inside. However this is currently painted as normal rock inside without any tyranid style features. This is for outside the mountain, however not sure what to do.
What do people think?
Does this look like a rock spire (when painted?)
or shold I convert this to a fleshy tyranid style structure?

