Painting of the Spiral Fresco by John Percival Droop. This example was found in the North West Fresco heap but was described by Evans as almost identical to one found in the Room of the Medallion Pithoi, and he used this image in the Palace of Minos to illustrate it.
Bibliography
Evans, Arthur. 1921. The Palace of Minos at Knossos, I, pp. 374-375, fig. 272
Myres, John (ed.). 1936. British Archaeological Discoveries in Greece and Crete 1886-1936, p. 20