Abstract: It is shown that there are some faces for which all possible ways of disappearance are probable in the same degree. This kind of faces may disappear by transformation to one of their edges or to a corner. On the other hand, there are faces which disappear in one way only, for example by transformation to one particular edge. Transforming to one of the other edges or transforming to a corner is impossible. It is shown that the way of disappearance of a given face may depend on geometrical conditions only. !4
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