There are several source code visualization tools available for choose. I've tried Code Swarm long time ago and this time I'd like to try something that can be done on web directly. So, here's the Gaia source code visulization rendered by CodeFlower via D3.js.
The prosperity of blossom denotes different
Orange is the settings app flower. The upperside are modulized setting panels. We can see good order of them. The downside crowds are things that not that modularized.
The purple sparkled flower is gaia web components. The main part is gaia-header, the top left part is gaia-grid.
The system app is a flower with a more concrete shape.
The calendar app (in yellow) looks like a pretty Dandelion.
What about others? go Gaia source code visulization and check by yourself. (The repo is a digest from 2015/1/7 master)
And you can make your own by forking CodeFlower from github.