They also have a satellite photo.
In this enlargement you can see the the road surface markings for what lane goes to which road.
Wikipedia's page isn't nearly as entertaining.
Conceptually that particular intersection is simpler than the one at Exit 17 off the Mass Pike in Newton: (satellite view).
Having driven through them both I think the Hanger Lane/Western Avenue one is better laid out than the Washington Street/Centre Street one, and certainly better marked.