Answer:
The stack just might be sent all over. Full of what's new, yet it's nearly obsolete.
What can you catch but not throw?
What hangs others yet can unintentionally hang itself?
A circle of stones, never in rows. Stacked one on the other, mystery it sows. What is it?
What looks back but cannot see?
What can you lose that will cause other people to lose theirs too?