A patch is a 721 that “extends” another NFT (721, 1155) or an account. A patch is soulbound to the patched target and by default cannot point to anything else. Patchwork Patches are mostly regular Patchwork 721s and can have Patchwork metadata. They can also be fragments but with soulbound ownership rules. Patchwork has 3 types of patches: 721, 1155 and Account.

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721 Patch

721 patches target an ERC-721 contract by targeting the address and tokenId. 
patchworkProtocol.patch(address owner, address originalAddress, uint originalTokenId, address patchAddress)
721 Patch contracts must implement the IPatchworkPatch interface and can be generated with the feature patch in a PDK contract configuration

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1155 Patch

1155 patches target an ERC-1155 contract by targeting the address, tokenId and account address. By using a 0x0 address for the account, you can target the entirety of an 1155’s tokenId. 
patchworkProtocol.patch1155(address to, address originalAddress, uint originalTokenId, address originalAccount, address patchAddress)
1155 Patch contracts must implement the IPatchwork1155Patch interface and can be generated with the feature 1155patch in a PDK contract configuration

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Account Patch

An account patch targets a plain address. 
patchworkProtocol.patchAccount(address owner, address originalAddress, address patchAddress)
Account Patch contracts must implement the IPatchworkAccountPatch interface and can be generated with the feature accountpatch in a PDK contract configuration