 There has been considerable discussion about whether the receptacle is to be thought of as matter, or as space, and whether it is possible to think of it coherently as having both of those roles. And there is also ongoing disagreement about the nature of the entities that are said to enter into and disappear from the receptacle. They are clearly not forms (52a4). Some interpreters have suggested that these are character types (or character tokens) derived from the forms, and that these types (or tokens) are properly the form copies (mimêmata) that have a prominent place in the argument for the receptacle (49c7–50a4). Whatever the merits of this reading, the things the receptacle is said to “receive” are “all the bodies (sômata)” (50b6). Bodies are three-dimensional entities, and this makes it likely that it is the emergence and disappearance of the variously characterized observable particulars as such, and not their properties (types or tokens), that are mentioned in these passages (49e7–8, 50c4–5, 52a4–6). But the particular bodies have a geometrical underpinning—the four “elements”, which are the building blocks of the physical world, are made up of the so-called Platonic solids; and these solids, in turn, are made up of two kinds of triangles (cf. below). 