I attended a demo of abstract painting recently and the artist, Aimee Baerg, had time to spare at the end. She asked what we would like to do and we said PAINT! So the attendees took turns to add to a canvas and I took pictures. Here is The process for the painting entitled "COLLABORATION".
Below are two versions of the video, which you may or may not be able to view.
(PS some names may be misspelled, I hope you forgive me)