It's not mentioned in the rules, but new dice generated will never have more sides than what's shown on the die you used to roll with. Moreover, if a die lands on a 2, that die will always land on 2 and effectively never be destroyed.
I suggest a new rule that prevents dice from ever having fewer than 3 sides, even if it lands on a 2 or a 1 so there's always a risk a die might get destroyed.