For Steiner $n$-chains of circles of radii $r_1,\dots,r_n$ tangent to an inner circle of radius $r_-$ and an outer circle of radius $r_+$, is there a Soddy-type relation between the $n+2$ quantities $r_1,\dots,r_n$,$r_-$, and $r_+$? <br /> ![SteinerChain][1] <br /> <sub>(Image from [Wikipedia][2] added by J.O'Rourke)</sub> [1]: https://i.sstatic.net/F96ZK.png [2]: http://en.wikipedia.org/wiki/Steiner_chain