A while back I got a couple of inquires about the birdcage side chair. This is a very tough chair because every part of the top it curved. Whenever I work on designs like this, I find it best to make a "Frankenchair" out of old parts and new ideas. They generally end up as ugly constructions of copper, tape and plywood. Without the help of a CAD program (I spend enough time at the computer) getting the right curves to intersect at the right places can be a real challenge. The visual and comfort aspect of the chair need to be refined simultaneously to get the desired result. I usually try to use enough quick joinery and tape to make the chair stable enough to sit on. Granted, you may not want to be too rough, but it's enough to give me and idea of the comfort level.
Here is a chair that I am currently working on. It is going to use curved stiles, crest rail, and spindles as well as arms. I plan to use simple joinery in the first solid prototype figuring that changing out some parts is probably in the cards. I will post progress as it comes.