Ok, that’s interesting, i never read this page before
What it’s saying is you can imitate an NFT by using statefull smart contracts.
Statefull smart contracts can write/update/delete values on the chain, this will give you this mutable touch you need. The main idea is if the NFT is not owned by anyone yet, the data must reside into the global storage. To give the property of this NFT to an account, you would remove this data from the global storage to the owner’s account local storage. So who owns the data owns the NFT.
Tho, i’m not certain this is a good design because done this way, the NFT cannot be transfered easily from one wallet to another like ASAs can. It won’t be compatible with services like NFTs marketplaces, and also algorand accounts can not opt-in to more than 10 statefull smart contracts while they are no limitations on ASAs.
I guess they are no concrete examples because it all depends what you really want to do.
But if you read about “Statefull smart contracts” you’ll find that writing values on the chain is trivial and to move the data from the global storage to an account’s local storage too.