  We consider a symmetric quantum communication scenario in which the signal
states are edges of a quantum pyramid of arbitrary dimension and arbitrary
shape, and all edge states are transmitted with the same probability. The
receiver could employ different decoding strategies: he could minimize the
error probability, or discriminate without ambiguity, or extract the accessible
information. We state the optimal measurement scheme for each strategy. For
large parameter ranges, the standard square-root measurement does not extract
the information optimally.
