This paper presents a “frame” representation for common sense knowledge and uses it to formalize our knowledge of “mundane” painting (walls; not portraits). These frames. while designed to aid a computer program to understand stories about the painting process, should be of use to programs which attempt to actually carry out the activity. The paper stresses a “deep” understanding of the activity so that the representation indicates not only what steps to carry out, but also how to do them, and (...) why they should be done. To accomplish this, while at the same time preserving modularity and nonredundancy, a system of interframe pointers is introduced (the COMES‐FROM and LEADS‐TO pointers) which explain how or why something is done in tens of knowledge given in other frames. The paper proceeds by steadily deepening an initial English‐like description of the activity, and a context free grammar for the representation is included. (shrink)