Ziggy has the best info I’ve found on reciprocal roofs at his Year of Mud website. See: How to Build a Reciprocal Roof Frame
A reciprocal roof is a simple self-supporting structure made of poles or dimensional lumber that are arranged in a spiral pattern. No center support is needed. They are perfect for round buildings. Developed by Graham Brown in 1987, this type of roof is extremely strong and can incorporate a living roof of plants. They’re fast to build. A reciprocal roof on a small house can be erected in a few hours. It is also affordable, since it can be made with peeled poles from a local forest. (Poles can be gathered with a low-cost firewood permit, typically costing around $25 or so.)
The basic process involves bracing the initial pole called a Charlie stick and then working either clock-wise or counter clock-wise, placing and tying poles in position. The last pole goes over the previous pole and under the Charlie stick. Then, just knock out the bracing under the Charlie stick and the frame is self-supporting. Secondary rafters can be added between primary rafters.
Check out Ziggy’s site for pics and complete details. He even provides a good list of resources for further reading.