Fungible Non Fungible Tokens

Inspiration

People often want to co-own an NFT, as explained in the article linked above. Implementing this using a traditional multi-sig wallet is a logical next step but this proposal brings several important improvements in terms of further closing the gap between decentralized and centralized financila systems:

As a Minority Owner (e.g. 20%), if the Majority decides to sell the NFT, I should still be entitled to 20% of the profit received.
As a Shareholder, I would like to be able to freely adjust my stake in the free market / exchanges. Stakes into this ERC721 token under this scheme are ERC20 tokens. A multi-sig wallet does not offer this feature.
We believe the above is an important step in enabling the creation portfolios of NFTs, such as using the Set Protocol
It is the logical next step in the evolution of a decentralized financial system. In the traditional financial system, high value items are rarely solely owned by 1 person.

Some concrete and easy-to-relate example use cases include representing an apartment co-ownership, selling fraction of an art piece, etc.

What it does

A wallet with a protocol that allows safe buy-and-sell of NFTs, to-and-from individual owners and a group of owners.

NFTs (ERC721) and their shares (ERC20) can be traded directly on DEX using 0x protocol in FNFT Wallet.
Create Set bundles of shares (ERC20) directly in the FNFT wallet.
The whole ecosystem, including 0x Exchange contract, some ERC721 tokens and an instance of the FNFT wallet contract, has been deployed to the POA Ethereum Network testnet.
Works great with mobile wallets such as Coinbase Wallet