On Polkadot, blockspace (called coretime) can be purchased in advance. The Lastic team is building a marketplace for coretime, and I developed a Solidity smart contract to crowdfund coretime so users can collectively buy access to Polkadot’s computation. The purchased core can be used to provide Polkadot’s economic security to L2 blockchains. The contract is fully tested with Foundry and deployed on Moonbeam.