Paul is a researcher at Adobe, working on 2D vector graphics, stylization, and non-photorealistic rendering (NPR). His thesis was in the area of 2D vector graphics editing, but his most noteworthy accomplishment was writing the first version of the software that eventually became the X Window System. After Stanford, Paul worked for three years at Digital Equipment Corporation, where he became the chief architect for the Xt Toolkit for the X Window System.