I have a set of black-and-white monitors, and a set of color monitors, which overlap the same area on the X-display. When the primary monitor overlaps the biggest monitor at least partially, there does not seem to be a way to have some screen saver cover all of my monitors. Instead, the following happens.
When the screensaver starts, it only runs on the biggest monitor, provided that the primary monitor is fully enclosed inside that biggest monitor (otherwise, the screensaver does not run at all). The other monitors only show the screensaver on the part of the screen that overlaps that biggest monitor; the other parts of the remaining monitors remain showing whatever they were showing before.
I realize from another thread that I cannot have the screen saver run on the entire display. Is there another way to do a simpler task of having the screen saver blank the screen on all three monitors?