Visual artist vonMash sits in his studio in Springs, South Africa, on February 7, 2022 as he works to create a Non-Fungible Token (NFT) for the online digital art market. - Digital art is nothing new to vonMash, who describes his blend of painting, video and sound as "afro-delic", a psychodelic twist on Afrofuturism. But when the South African started thinking about selling his work as crypto-art on a blockchain, he hesitated. Selling art as non-fungible tokens, or NFTs, uses the same technology as crypto-currencies like Bitcoin. The buyer receives a verified digital token, which proves the artwork is an original. What worries vonMash and other artists is how those digital tokens get verified. Ownership of the artwork is authenticated through complex math puzzles, so complex that the calculations require warehouses of computers. Companies who solve the puzzles get rewarded with new tokens, and their solutions add a "block" to the chain of the authentification. Those calculations suck vast amounts of energy, often produced by coal-power electricity plants. (Photo by LUCA SOLA / AFP)