NULL sees every block. It just will not tell you which one.
Your answer
Submit it here
Everyone can enter. The earliest correct entry wins. Your answer is
checked on this device and only a hash is sent, so a wrong guess costs
nothing and stays private.
1 Lock it in
2 Open it
3 Collect
answers look like LANTERN-K7X4RQ2M9VNH3TYB
locked into your entry, nobody can redirect it later