The Pigasus was used by John Steinbeck as a personal stamp with the Latin motto Ad astra per alia[1] porci (to the stars on the wings of a pig). The pigasus was supposed to symbolize Steinbeck as "earthbound but aspiring.... A lumbering soul but trying to fly...(with)...not enough wingspread but plenty of intention."
Coincidentally, Pigasus was a character in the Oz books written by Ruth Plumly Thompson in the 1930s.[2] Her Pigasus was also a winged pig. As with Pegasus, his riders gained the gift of poesy, speaking in rhyme while on his back. The character first appeared in Pirates in Oz.
John Steinbeck occasionally drew this on books that he signed at book signings. These books are now worth considerably more than ones with just his signature on it.