What is a question about this article? If the question is unanswerable, say "unanswerable".

The panel is eventually broken apart into individual PCBs; this is called depaneling. Separating the individual PCBs is frequently aided by drilling or routing perforations along the boundaries of the individual circuits, much like a sheet of postage stamps. Another method, which takes less space, is to cut V-shaped grooves across the full dimension of the panel. The individual PCBs can then be broken apart along this line of weakness. Today depaneling is often done by lasers which cut the board with no contact. Laser panelization reduces stress on the fragile circuits.

Individual PCBs can be merged along what line?
unanswerable