1917 print of same mask stack (mislabeled as 3rd door in Seler's caption). "Fig. 59. Uxmal. House of the Nuns. North building. Inner or main facade (south front). First (lowest) and third and fourth masks of the mask column B above the third door (counting from the west end)."
Scanned from Eduard Seler, “Die Ruinen von Uxmal”, 1917 (fig. 59).