Dutch type designer. Started the LettError virtual type foundry with Just van Rossum, with whom he worked at MetaDesign. Fame came with the release of Beowolf (co-designed with van Rossum), a font whose ragged edges shift randomly each time you print the font. Another font of his, Kosmik, has a version that flips between three alternates for each character for a more friendly, hand-drawn feel. Most of his fonts are published by FontFont. He is a key developer on the Robofog project with van Rossum and Petr van Blokland.