Contemporary frame-and-panel construction involves detailing the inner edges of the stiles and rails with decorative profiles (shapings), along with a slot cut beneath the profile to accomodate the floating panel. The traditional method of joining the rails to the stiles was to use a stuck mortise-and-tenon joint, however modern production requires a less time-consuming, more economical joint. The advent of shaping machines such as the router gives us the ability to quickly, easily, and most importantly accurately produce a joint suitable for profiled framing joints.
The cope-and-stick joint (or cope-and-pattern joint) is formed by with two different profiles. The first pass through the shaper adds the interior profile to the stiles and rails. Once all the pieces have been shaped, the ends of the rails receive a second pass that gives them an inverse of the first profile. This allows the ends of the rails to be neatly inserted into the profile of the stiles, and essentially forms a groove-and-stub-tenon joint. This produces only slightly more glue surface than a groove-and-stub-tenon joint, however it adds a great deal to the visual effect of the panel.