I first learned this game from Holly, my daughter, who learned it from Caiti Hankins.
Holly wrote up the directions for me:
The directions leave out a few things. You fold the paper under after you draw or write. Each player sees only one thing with this exception: The third player sees the full sentence. Neither of the half-a-sentence writers knows the full sentence.
There are as many papers as players, and all play at the same time, and the papers are passed one direction or another all at the same time (and you might want to change rotation after a few, or rearrange players at the table). It needs at least three players, and can have as many as you have room for.
The last important thing is that the number of pictures isn't crucial, but when the round is over, and you pass it with a sentence as the last play, you say "Merry Christmas" to the person you give it to, who then reads the final sentence aloud. After they're all read aloud, they can be passed around unless you can't wait to start another set.
Here are some samples I scanned from some that Holly saved from sessions at the house. Some only went around for two pictures, and some for three. None did four as the directions show, so don't get attached to a number of times it needs to pass, just so that when people are ready to quit the last play was a sentence.
TIME OUT: That last "writey" is faint, and was clarified later anyway. It was "One cat gave another a flower but ended up at a lonely tea party anyway."
The final sentence was a perfect description of the last drawing above: