Place, Space and Motion in Plato and Middle Platon (Topoi D-II-2)

How does Plato use spatial concepts in his natural philosophy (to the extent that he has one)? How did Middle Platonist thinkers, especially Plutarch and the author of the Didaskalikos (= Alcinous?), take up and revise Plato’s views? To what extent were they also influenced by other thinkers, e.g. Aristotle?