The long running project AB UNO/AD UNUM about the number ONE in languages of the world and divided in three continents: Eurasia, Africa and America – respectively in black-white diptychs, polychromatic dyptichs and monochromatic diptychs – has been on show in galleries and museums in for instance Groningen (NL), Karlsruhe (DE), Dortmund (DE), Bonn (DE), Düsseldorf (DE), Krefeld (DE), Lingen (DE).
THE GRONINGER MUSEUM, Groningen, 1998. Exhibition: Ton Mars, Ab Uno/Ad Unum (Eurasia: black-white diptychs). [Photography John Stoel]
STAATLICHE KUNSTHALLE KARLSRUHE, Karlsruhe, 1998. Exhibition: Ton Mars, Ab Uno/Ad Unum (Eurasia: black-white diptychs). [Photography Kunsthalle Karlsruhe]
GALERIE CORA HÖLZL, DÜSSELDORF, 1999. Exhibition: Die Welt ein Zeichen (Eurasia and Africa, respectively black-white and polychromatic diptychs + a wall drawing with the number ONE in different languages of the world). [Photography John Stoel]
MUSEUM AM OSTWALL, Dortmund, 2001. Exhibition: Ton Mars, WeltenSammler (Eurasia and Africa, respectively black-white and polychromatic diptychs). [Photography John Stoel]
KUNSTHALLE LINGEN, Lingen, 2002. Exhibition: Qual der Zahl (America, Eurasia and Africa, respectively monochromatic, black-white and polychromatic diptychs). [Photography John Stoel]
