A piece that stays sealed until the raffle's block is mined, then draws itself from that block's hash. The same hash that picks the winner finishes the prize.
The grey zeros at the front are the proof of work. Every block has them, so they're useless for picking traits. The last 16 characters are where the randomness is, and each coloured pair decides one trait.
Each tile is a different possible block. Click one to inspect it above. Nobody, not even the artist, knows which one will be real until the block is mined.