Bitcoin Art Marathon: Exploring Block Building Visualization

A Bitcoin Core contributor has created a unique piece of “block art” by using Marathon Digital’s template building tools to immortalize the company’s logo into a Bitcoin block’s data visualization. The graphic was created by ordering transactions in a block and can be seen on a Bitcoin indexer website. These indexers use color gradients and square blocks to visualize bitcoin transactions based on transaction sizes and fee rates. Marathon Digital, a mining firm, mined block 836361 on March 26 and named it the M block. The purpose of the visualization was to showcase the company’s template building capabilities and technology stack. Although Marathon does not offer this specific service, it believes that there may be untapped creative potential in the Bitcoin space.

Portland.HODL, the user responsible for the block art, claims to have successfully crafted the visualization through a trial and error process. To create this artwork, OP_RETURN transactions in the Bitcoin protocol were used. These transactions allow for a small amount of arbitrary data to be included, typically used for embedding messages or metadata on the blockchain. By carefully crafting the content of these transactions and ordering them correctly, an image or pattern can be visualized when looking at the block data.

Creating block art requires miners to modify their software to select specific transactions that will form the desired pattern instead of prioritizing transactions for maximum profit. Mining a block with a specific set of transactions for an image or text requires significant hashing power, like that of Marathon. The company suggests that excluding these blocks from full pay-per-share calculations would ensure more accurate miner fee estimates and prevent any impact on network fees.

There is still much to learn about the “M block” and the implications of block composability. has reached out to Marathon and Portland.HODL for further details on this unique creation. In February 2024, Marathon launched a direct BTC transaction submission service to facilitate and expedite large and complex Bitcoin transactions.