This is a personal project getting to know D3's force layout and using some personal libraries - io-grid and jet-color.

D3's force layout doesn't seem to have a native way of recording velocities, which I bind to the color of each node, so I recorded that myself within each force tick. This augmentation is clearly marked in the code.

Although this example looks a lot like this, their implementation is actually quite different. Specifically in the use of links.