 In this subsection we will discuss an interesting sense in which, in STR, the letter (if not the spirit) of classical relationism can be considered vindicated: the spatio-temporal relations between material things are, on their own, sufficient to fully determine the state of motion of a body. The discussion here presupposes acquaintance with STR and its basic mathematics, and will be hard to follow for readers lacking that background; such readers should feel free to skip this subsection, which is not necessary for following the material in the rest of section 2. 