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Placeth is a crowd-sourced pixel art board where the community coordinates entirely on-chain. In placeth, art is collaborative; and, like a graffiti wall, the pixels are ephemeral


Created At


Winner of


🥈 The Graph - Best Existing Subgraph

Project Description

Placeth is a crowd-sourced pixel art board where the community coordinates entirely on-chain. In placeth, art is collaborative; and, like a graffiti wall, the pixels are ephemeral. Placeth is permissionless, anyone can tag/paint over anyone else's pixels. Art can however be preserved, if the community decides the pixels are worthy. Leveraging the Graph, data-availability on-chain is minimized and intensive indexing is pushed onto the graph, so placing pixels on-chain is made so cheap that it's reasonable on mainet Eth. Leveraging Reality.eth and Kleros, the decisions to preserve art is crowd-sourced and placeth is owned by the community.

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Unlike Banksy street art, we can't cut art out of a wall --- but we can cut an erc-721 out of the pixels placeth. Is every pixel worth preserving? What even is art anyways? --- beauty is in the eye of the beholder. Art isn't really something that an individual owns anyways, its a reflection of the society that produced it. In placeth, preserving art immortalizes pixels the limited real estate of the 65536 x 65536 canvas. Like a statue in a town square, we want the community to decide which pixels to preserve. We use Reality.eth backed by Kleros as a subjective oracle to crowd-source the question "is this art?".

How It's Made

The state changes to placeth are registered by calldata passed on-chain (deployed on Eth Kovan testnet). Placeth leverages the graph for data availability. Pixels are encoded in 5 Bytes, 2 Bytes for each coordinate, and 1 Byte for color. Each pixel change costs 80 gas, so encoding a cryptopunk (24x24) pixel art on the graffiti wall costs ~ 45k gas (~$10 at 80 gwei gas on mainet). The Graph handles indexing the calldata with event and call handlers. No storage about the pixels are maintained on-chain, the graph ensures data availability for the front-end rendering of the entire canvas.

Placeth integrates Reality.eth, a bond escalation mechanism along with Kleros arbitration services to have a decentralized and fair source of truth. (see example question below)

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When users request to preserve an area of placeth, a question is created on Reality.eth (currently on Kovan testnet). Moreover, users stake a small deposit proportional to the number of pixels in the requested area and anyone can challenge the request for a period of 1 day. If anyone in the community thinks the requested area is not art, then they can play an escalation game doubling the bond. Moreover, any user can request arbitration from Kleros, a decentralized justice protocol, to resolve the question.

After a challenge period of 1 day, if the art preservation request is accepted, then an erc-721 is minted to memorialize the event. Moreover, the pixels are 'frozen' in the graph and the area cannot be rewritten.

How it's Made

The Graph and React.js with TypeScript. The frontend dev (Green, talking 3rd person rn) didnt ever use canvases in html. The Graph is the kind of architecture that makes this dapp a possibility in the first place, this dapp relies on off-chain, decentralized data availability, but it coordinates using the blockchain. We were surprised we even managed to get close to making it, unfortunately we couldn't show the whole project in the extent of the hackathon, but, it's still a fun project to show. .... Stuff that's worth mentioning, first of all, this is cheap enough to be deployable in mainnet, it's just 80 gas per pixel (5 bytes). In order to have the subgraph exert less effort returning the data, we compress the pixels onto chunks. We also leverage Reality.eth which in turn is supported by Kleros. It works in the contract, but the frontend couldn't catch up. After going back to pick my stuff in the hotel I realized I could've used translate for the map, its so unperformant right now because it draws redundant information.

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