Silk Penetration/Transposition Panels. European, 1920s. Orange and blue silk handkerchiefs, stretched tightly in wooden frames, transpose locations from one frame to the other when covered. Entirely mechanical and instantly repeatable. Clever mechanisms hidden in each frame. With a third matching frame and cover that allows a blue silk to be pierced by needles or vanish from the frame. Each set 9 ? x 9 ??.