Single extra sheet, coming from famous artist book "Throwing Three Balls In the air to get a straight line"

Single extra sheet, coming from famous artist book "Throwing Three Balls In the air to get a straight line" Milano, Prearo /Toselli 1973. Edition of 2000 un-numbered and unsigned copies. In this extra sheet the immortalized balls are 4 instead of 3 as in the other 12 sheets. No text, not signed. Very rare. It is presumed derived from some editorial evidence during the design of the famous artist's book by Baldessari and inserted into some copies of the edition. Singola tavola extra, proveniente dal libro d'artista "Throwing Three Balls In the air to get a straight line" Milano, Prearo /Toselli 1973. Edizione di 2000 copie non numerate e non firmate In questa tavola le palle immortalate sono 4 invece di 3 come nelle altre 12 tavole.Molto rara. Si presume derivata da qualche prova editoriale durante la progettazione del famoso libro d'artista di Baldessari e confluita in alcune copie della tiratura