When a bunch of musicians get together and there are instruments at hand, it's not unusual for a jam session to happen, with everybody pitching in and lending their musical voice to an impromptu improvised piece. Comics creators are like that too. These jams are created at our meetings, without any idea ahead of time of where they were headed. Each person would add a panel or two, and pass it on to someone else to continue, pretty much at random. Sometimes they get stuck (as in "traffic jam"), but the results can also be sweet - and lumpy and sticky - (as in "strawberry jam").