Circles aren't real.

You can't draw a perfect circle, hence they are not real. Anyone who thinks otherwise is a fag.

Plato's Theory of Forms asserts that Forms (or Ideas), and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. Plato spoke of forms (sometimes capitalized in translations: The Forms) in formulating his solution to the problem of universals.

Plato postulated a world of ideal Forms, which he admitted were impossible to know. Nevertheless he formulated a very specific description of that world, which did not match his metaphysical principles. Corresponding to the world of Forms is our world, that of the mimes, a corruption of the real one.

No one has ever seen a perfect circle, nor a perfectly straight line, yet everyone knows what a circle and a straight line are. Plato utilizes the tool-maker's blueprint as evidence that Forms are real: when a man has discovered the instrument which is naturally adapted to each work, he must express this natural form, and not others which he fancies, in the material.