This is an original digital watercolor brush I made while I had a collaboration with Adobe in 2010. Adobe further worked on the algorithm and released an iPad app, called Adobe Eazel using the algorithm. It acts like watercolor as you paint.
S. DiVerdi, A. Krishnaswamy, R. Mech, D. Ito. “A Lightweight, Procedural, Vector Watercolor Paint Engine.” In the Symposium on Interactive 3D Graphics and Games, Mar. 9-11, 2012.Best Paper Award.