Vitalik Buterin has proposed a new way of looking at Layer 2, suggesting that the term should not be limited to Rollup. In his article, he argues that there are multiple ways to achieve Layer 2 scaling on Ethereum, including Plasma and Validium.Plasma is a popular solution that restricts Data Availability (DA) to the mainnet, while Rollups allow for DA both on the mainnet and off-chain. However, Vitalik believes that layer 2 should be defined based on security preferences, creating two categories: Strong L2 and Light L2.Validium offers a more flexible solution by allowing DA entirely off-chain, with the final state synchronized to the mainnet using SNARKs. Vitalik argues that Validium is safer than some Rollups that rely on multi-signature governance for security. He believes that stricter Rollup solutions are also more secure and can ensure data's chain-on availability and integrity.He also points out that Chain-on SNARKs + Chain-off Data are more secure than pure Chain-on Fraud Proofs + Chain-off Data, as the former ensures data consistency and integrity on-chain. Vitalik emphasizes that Rollups do not equal Layer 2 and suggests that Plasma and Validium have many opportunities for innovation.In conclusion, Vitalik's new perspective on Layer 2 could help prevent Ethereum from being limited to a single scaling solution, potentially leading to more diverse and resilient scaling options in the future.