Stephen pointed to a basket which a butcher’s boy had slung inverted on his head.
—Look at that basket—he said.
—I see it—said Lynch.
—In order to see that basket—said Stephen—your mind first of all separates the basket from the rest of the visible universe which is not the basket. The first phase of apprehension is a bounding line drawn about the object to be apprehended.
(James Joyce, A Portrait of the Artist as a Young Man, Chapter V).