Ethereum Virtual Machine (EVM) was originally designed for the Ethereum main network. Nowadays, however, most teams no longer want to reinvent blockchain from scratch; instead, they'd like to take EVM beyond Ethereum. We've seen a lot of blockchain teams choose to fork Ethereum (e.g., Quorum) or implement the EVM spec (e.g., Burrow, Pantheon), adding their own designs. The intention is to not only reuse the Ethereum design but also leverage its ecosystem and developer community. To many developers, the concept of "smart contract" is almost equivalent to a smart contract written in Solidity. Although Ethereum itself has some constraints, the technology around the EVM ecosystem is booming.