NOTDEF is a pseudonym for Sibe Kokke, an independent multisisciplinary graphic designer based in Rotterdam. Since 2008 passionately working on conceptual design, typography and creative coding for both printed and digital media.
Inspired by critical research, experiments, open discussion, beautiful accidents and practical common sense notdef explores the fields of printed matter and (interactive) digital media. Resulting in a variety of products; posters and flyers, identities, logos, typefaces and lettering, creative software, installations and performances, live shows, sound design, (human) interfaces…


NOTDEF is working in a broad field of design and finds collaborations were needed. In the past notdef worked together with a variety of artists: (an incomplete list in pseudo-random order)
Dirty brown Visuals, Daniel Oliveira Prins, Thijs de Jong, Eva Uppenkamp, State of Monc, Menno Verhoef, Ineke Kruizinga, Ik heet Welkom, foundation “de Fabriek”, Hanco Kamper, Charlotte Aal, Hotel Modern, Kamiel Verschuren, Anton Klein.

NOTDEF makes use of (opensource) software / tools that earn some notice here: processing and processing.js, openFrameworks, drawbot, arduino.


Maassilo Rotterdam, Willem de kooning academie, Pessenger Terminal Amsterdam, Lowriders recordings, Atelier Tarwewijk, Stichting de Loodsen, Zuiderparkspelen, Circus stad Rotterdam, Djemaa el Fna, eetplein Rotterdam, Lino hellings / PAPA, Hotel Modern, Stichting Ik heet Welkom, Bureau TamTam, Ella nitters, Francois Lombarts, Jeanne Works, State of monc, Branson & Guevara, Stichting Scrap, Studio Bassa, Monsieur Dubois, Keisshin Barrett, CODarts, Stichting de Fabriek, Dirty Brown Visuals, DOP design, nic.Oud, Modefabriek Amsterdam RAI, Blikopener Festival