Ethereum smart contract security badge design

[EtherDotBlue]

The Ethereum Trust Alliance is about to launch a new system where smart contracts that have passed certain levels of security tests can be added to a registry and awarded badges that will be displayed on their web sites (larger) or within MetaMask or Etherscan (small). We are looking for designs for 3 levels of trust - think bronze, silver, gold or 1 star two stars three stars for Michelin restaurants. But these should signal Ethereum security. Color alone may not be enough to differentiate the levels and we are looking for a creative design that scales in size.