#plasma $XPL 1. The core pioneering contribution of Plasma: It was proposed by Joseph Poon and Vitalik Buterin in 2017, and its core idea is the tree structure of 'subchain-mainchain'. It allows for the creation of a large number of 'subchains' outside of the mainchain (such as Ethereum) to handle transactions, only submitting the final state commitments or dispute proofs back to the mainchain. This greatly demonstrates the possibility of off-chain large-scale transaction processing, with the mainchain ensuring security, igniting the spark for all Layer 2 scaling solutions. @Plasma