In brief

  • Someone has solved 0xPoland's puzzle, claiming 7 ETH as a reward.
  • Starting with a billboard in the Warsaw metro, a group of Ethereum enthusiasts tweeted several clues over 10 days.
  • After the last clue was published, It took only 21 minutes for the winner to claim their prize.

The Ethereum-focused puzzle that started with a mysterious billboard in the Warsaw metro has been solved, awarding the winner 7 ETH (worth roughly $4,115 today), the event’s organizers announced last Friday.

As Decrypt reported, an enigmatic billboard appeared in one of Poland’s capital metro stations on November 16. It called on commuters to “Solve the puzzle, claim the reward!” and contained an Ethereum address with 7 ETH on it, as well as hashtags #0xPOLAND and #0xPOLANDHEIST.

Simultaneously, a Twitter account dubbed “0xPoland” started posting some cryptic messages accompanied by bunny rabbits, and later—clues. But the very first lead was hidden in the Ethereum contract’s code itself, the organizers explained. First of all, the winner needed to call the “solve” function and use a secret phrase as a parameter to withdraw the funds.


The first clue was published three days later. It contained the phrases “Tip: ^[A-Z].*.” (which implied that the secret message must start with a capital letter and end with a period), and “0x01ccfbfc”—a piece of the solution’s control sum.

The image in 0xPoland’s tweet also read “Bring my light, light by my side, light of the burning tower”—a quote from “Into the dark forest” song by black metal artist Elffor. Thus, the first part of the secret phrase was “Into the dark forest.”

On November 23, 0xPoland tweeted “Answer to the Ultimate Question of Life, the Universe, and Everything” and a long string of characters. The first one was an obvious nod toward The Hitchhiker’s Guide To The Galaxy (so “42”) while the string required some programming skills to decipher. Ultimately, the second part of the passphrase was “Down the rabbit hole.”

The third and final clue was published in Polish newspaper Gazeta Wyborcza (both online and on paper) on November 26, although it was a whole new challenge all by itself, 0xPoland explained.

0xPoland's ad in Gazeta Wyborcza
0xPoland's ad in Gazeta Wyborcza. Image: Twitter

“We decided to place an ad in a Polish newspaper. It’s much harder than it sounds! Quite a few daily newspapers declined our ad as they couldn’t wrap their head around the concept of the puzzle and preferred to play it safe,” the organizers noted.

The ad said “You’ve come a long way. I’ve got your last clue. Call me ASAP,” and provided a phone number that redirected users to a pre-recorded message containing missing elements of the full passphrase. Ultimately, the winner needed to input “With 0xPoland. Into the dark forest. Down the rabbit hole. Where adventure awaits.”

After that, it didn’t take long for the winner to claim their prize.

“21 minutes after posting a Tweet pointing to the page in the newspaper we saw the winning transaction. The correct hash was committed to the smart contract and three minutes later the transaction solving the puzzle was confirmed. A few hours later the anonymous winner transferred his hard-earned 7ETH to his wallet,” 0xPoland noted.

But why did the organizers go to such lengths to arrange this event? As it turned out, mostly to have some fun and to shake polish Ethereum enthusiasts up a bit.

“We are closely watching the polish Ethereum developer community and felt like it could [be] a little adrenaline rush!” adding, “Apart from some fun, we wanted to offer a place for developers to grow their skills and join us in building the Decentralized Finance infrastructure.”

In the end, organizers revealed that 0xPoland is actually the name of a series of meetups, workshops, and hackathons for blockchain developers, with the first event scheduled for December 8.


That’s certainly one way to get the word out.

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