Here’s my solution (it’s the one from the book):
And here’s the link:
http://www.lodev.org/jstumble/?board=rrereree0eleeblleelgbleelrxeereireereereereereereelr
Description: This one seems tricky at first, but it’s not all that bad. It is just a rearranged version of this:
Here, the top bit and the gear bits create 4 unique ball paths that depend on the 4 possible initial directions of the bits. All we have to do is direct two of the paths to the interceptor (see the blue paths below) and the other two paths to the to the red flipper (see the red paths below).