You may refer to a truss as the rafter, but it's basically the skeleton of the roof, carrying the weight of the frame and supporting the walls of the building. Trusses are very important to preventing the walls from bending or flexing, more so.
"How to make a pebble mosaic," Excellent step-by-step instructions from "This Old House." I just need to sort our stones, get more stones, and layout the design. This would be a good project to start in September.