Dear Bankless Nation,

On Ethereum, and besides the base constraints of the Ethereum Virtual Machine (EVM), the programmable possibilities around NFTs are limited only to our imaginations thanks to smart contracts.

As for Ordinals, a.k.a. Bitcoin NFTs, they face a different set of tradeoffs in being inscribed on individual satoshis. One of the downsides here? The lack of composability and expressiveness that smart contracts offer.

However, the Ordinals community has innovated a sort of native workaround here known as recursive Bitcoin inscriptions. They’re not smart contracts, of course, but they do notably bring dynamism to Bitcoin NFTs.

This type of inscription use is on the rise as more Bitcoin projects are embracing the technique, so for today’s post let’s get you up to speed on the basics of this new innovative method!

-WMP

An Intro to Recursive Bitcoin Inscriptions

When it comes to Ethereum NFTs, composability and dynamism come via smart contracts.

For example, regarding composability, Ethereum NFTs can be readily built on and around through integrations with other smart contracts, like those seen in the protocols of the rising NFTfi lending sector.

And as for dynamism, Ethereum NFTs can tap smart contracts to evolve upon certain conditions being met, e.g. a transfer to a new wallet, or in real-time via code running in the always-on EVM.

In contrast, Ordinals, which burst onto the NFT scene in 2023, don’t enjoy the benefits of smart contracts, which aren’t native to Bitcoin—hence “Bitcoin L2s” like Stacks.

Yet take note, because this lack hasn’t stopped Ordinals builders from establishing their own Bitcoin-centric versions of NFT composability and dynamism via recursive inscriptions.

What Are Recursive Bitcoin Inscriptions?

If you recall, minting Ordinals entails inscribing data—images, videos, texts, game emulators, etc.—onto satoshis, the smallest denomination of Bitcoin.

In the context of Ordinals, then, recursion refers to the ability of one inscription to access and use the content of other inscriptions.

This technique can be achieved by tapping specific “recursive endpoints,” like r/sat, which is usable for fetching the initial 100 inscription IDs on a particular satoshi.

Accordingly, recursive Bitcoin inscriptions allow projects to effectively bypass the typical data limitations of Bitcoin’s 4 MB block size limit, enabling more extensive and intricate digital creations atop the OG blockchain.

This method has also notably paved the way for composability and dynamism in Bitcoin NFTs, as recursive inscriptions work well for things like sharing resources (openly usable audio, code, images, etc. on Bitcoin) and content remixing (modifying existing inscriptions on Bitcoin).

The Recursive Inscriptions Landscape

Initially, Ordinals were siloed content—an inscription wasn’t aware of anything but itself, so to speak.

Then the OnChainMonkey (OCM) project helped pioneer the recursion method with the design of its OCM Dimensions collection, which it first inscribed on Bitcoin back in February 2022.

In deploying the OCM Dimensions, the OCM team uploaded the p5.js creative coding library via inscriptions and then used recursive inscriptions to ping p5.js to build out the collection.

This innovation expanded the landscape of possibilities around Ordinals and led to a surge of new creative efforts, like generative art releases, on Bitcoin.

The popularization of recursion led the developers of the ord protocol, the system underlying Ordinals, to officially integrate recursive inscriptions starting with the ord 0.6.2 and 0.11.0 updates.

Since then, a range of projects have begun embracing recursive inscriptions toward new ends. One area where this method is gaining a lot of traction presently is in Bitcoin’s PFP sector, where collections have started uploading their traits via inscriptions and then using recursive inscriptions to build out 1,000s of unique digital collectibles.

A team breaking ground here right now is Bitcoin Pizza Ninjas, which is using recursive inscriptions for its art generation and upgradeable traits. The builders have even deployed a Super Nintendo emulator on Bitcoin that its ninja characters can play within via recursive inscriptions.

Another project worth tracking currently? Quantum Cats, a collection by the Taproots Wizard team that’s using recursive inscriptions and other new techniques to build the project out in the open but without revealing the completed art ahead of its official release.

Trying Recursive Inscriptions

As a regular end user, there’s nothing special you have to do to access the capabilities of recursive inscriptions—you simply collect from projects that employ this method and then enjoy however they use it, e.g. upgradeable PFP traits.

However, you will need a Bitcoin wallet that offers support for recursive inscriptions, as many don’t. Two wallets that do offer such support currently are Leather and Xverse.

With either of these browser wallets in hand, you’ll be able to own and manage your Ordinals, recursive or otherwise, in non-custodial fashion. As they say, not your keys, not your Bitcoin NFTs!

The Big Picture

With projects like Bitcoin Pizza Ninjas and Quantum Cats pushing the boundaries of what’s possible with recursive inscriptions, we’re entering a new era of digital collectibles on Bitcoin.

While it still lacks all the power of smart contracts, this emerging technique not only circumvents the data limitations inherent in Bitcoin’s architecture but also introduces layers of interactivity and dynamism that were previously unattainable on the OG blockchain.

In other words, love ‘em or hate ‘em, recursive Bitcoin inscriptions are just another reason why Ordinals are here to stay. As such, look for further booms around Bitcoin’s art, gaming, and PFP scenes going forward as more and more projects start experimenting with linking inscriptions with other inscriptions!