Perhaps the most characteristic artifacts other than pottery found with any frequency at Mycenaean sites are the small, vertically perforated conoid objects described as spindle whorls or buttons, although neither use has been satisfactorily proved. They occur in several shapes. Persson distinguished the purely conical type with or without a rounded top from the shanked and the disc-shaped; Wace divided them into conical, shanked, shanked with concave base, and biconical; Blegen into bicones, short cones, and shanked; Furumark into conical (Type a 1), biconical (a 2), shanked (b), and disc-shaped (c). They belong, that is to say, to five basic types: bicone, semi-globular (Persson's round-top conical), conical, shanked, and flat or disc-shaped (Fig. 1), with variations in the shape of their bases (flat or concave) and of their tops (plain or ringed).