Glass "logs" heating up in a pie pan on the hot plate. When set to "medium" this gets hot enough that some colours start to strike. I would rather have a heavier pan, because this cheapo thin pie pan flexes weirdly when heating or cooling; it rocks, it wobbles, it creaks. A cast iron pan would be better, though it would take longer to heat up.
These logs are shorter than what I would use at present; I'm getting ambitious and making larger marbles.