This was an activity organized among a few UCSD Chinese painters. The host chose a picture as the starting point (the last picture in the long image). Each player only sees what the previous player has drawn, and he/she needs to draw a new painting that's similar to the previous one, but can intentionally add/change some elements.
That's it! There is no guessing, winning or losing. Seeing how the painting evolves is extremely entertaining.
Now get ready for the full history of the activity (sorry no English translation)