English: Photograph of “Iki-piirto” writing pad, a Finnish variety of Printator, known in German language as “Wunderblock”, as described by Sigmund Freud in his essay “A Note upon the ‘Mystic Writing-Pad’” from 1925. This writing aid has allegedly been used in Finnish schools circa 1950s when teaching mathematics, as there is a multiplication table on the backside (see “Other versions”, below).