There is an interesting graphical analog for fuzzy equivalence relations. An inspection of a three-dimensional plot of the preceding equivalence relation, R ∼ 3 1, is shown in Figure 3.11. In this graph, which is a plot of the membership values of the equivalence relation, we can see that, if it were a watershed, there would be no location where water would pool, or be trapped. In fact, every equivalence relation will produce a surface on which water cannot be trapped; the converse is not true in general, however. That is, there can be relations that are not equivalence relations but whose three-dimensional