If the public chain is regarded as a community and a nation, then the structure of L1, L2 and L3 is reasonable, and the flat structure such as sols is unreasonable, is it not? If mass adoption is regarded as the goal of the blockchain, and the needs of different applications are different and may vary greatly, how can the main network fully satisfy it? By outsourcing the execution layer, each L2 can better meet the personalized needs of different applications, and even use different languages and VMs (e.g., arb), L1s do not pursue excessive value capture, and L2s capture more value from their own on-chain operations, so as to incentivize compatibility and mobilize motivation to promote adoption, and grand unification is undesirable. Centralization and effective governance are contradictory, it is the L2s that understand the needs of each application better than the L1s, and decentralization of financial and administrative power is the only way to incentivize the L2s to adapt to local conditions.