The heart of Plato’s framework in talking about abstract forms, which you could also say is about the real versus the ideal (or, perhaps more accurately, his construct of reality), is found in Books 6 and 7 of The Republic (507a-521b) through three metaphors: the sun, the divided line, and the cave.
In the last few months, I have also realized that my work, in its current style, is a meditation on ideas from two different strands of ancient Greek philosophy, Platonism and Stoicism.