While researching the CO2 footprint of the Ethereum (ETH) cryptocurrency chain, media artist Kyle McDonald discovered ‘graffiti’ early miners left in ETH blocks using the “extraData” field. “One miner operating in 2016 decided to tell a story: one word per block, over 2.5 months,” McDonald writes on Twitter. “Maybe one of the slowest monologues ever” was mined over 129 blocks for 648 ETH and had a happy ending: “it looks like they cashed out early this year, for around half a million USD.”