<human>: How do you do this: How can I create marbles with a shattered glass effect?

OPTIONS:
- Gather marbles, set oven to 400F, place marbles on baking sheet and bake for 20 minutes. After 20 minutes remove marbles and immediately submerge in hot water.
- Gather marbles, set oven to 400F, place marbles on baking sheet and bake for 20 minutes. After 20 minutes remove marbles and immediately submerge in ice water.
<bot>: Gather marbles, set oven to 400F, place marbles on baking sheet and bake for 20 minutes. After 20 minutes remove marbles and immediately submerge in ice water.