Male siphon block

Perforated limestone block of the inverted siphon pipe of the Aspendos aqueduct. This side is
the 'male side' of the block. Notice the round smoothed surface around the central perforation that
was used to make a waterproof seal; the outer edges of the square block were not part of this seal.
Near the Seljuk bridge on the Eurymedon. Photograph Cees Passchier