The whole concept of a fixed bot is kind of weird IMHO and is inelegant and unrealistic from a physcis perspective (so are moving shapes BTW). As an example, fixed bots are treated as if they mass 32000 for the purposes of collision elasticity.
Fixed veggies used to be important for topological reasons, creating poor-man's walled nursuries for zero bots for example, but shapes can fill that role now.
Having fixed veggies is interesting as a means of creating topological separtion and thus species isolation in large evo sims, but since fixed bots can be unfixed, this is only so effective for so long. Fixed veggies get unfixed after a few million cycles for example in my southpacific sim as soon as some bot mutates to shoot the right memory shot. Were I to do such a sim again, I would use shapes to acheive topological isolatiuon.
About the only thing I like about the whole concept of being fixed it is that it enables a class of bots which use it as a proxy for gripping and ungripping the surface as a means of locomotion such as Inchworm.
Perhaps what we need is to do away with the whole concept of fixed all togther and replace it with a mechanism that allows bots to change their coeffecient of static friction as a means of rooting themselves. This would allow for rooted plants and inchworm style bot motivation, but such bots could still be displaced soem ways by a large enough impact. Note that my vision for shapes is that they too will have mass proportional to their size and that it will be possible for the shape itself to be the one deflected...
Anyway, in the near term, I could probably make it so that fixed veggies separate until they don't overlap when a shape sweeps them or when they materialize or teleport on top of one another. Moving shapes would still sweep them into clumps, but the clumps would not overlap, at least not for long.
