[todd8]

On some early graphical computer user interface, I can’t remember which one, one could specify that the mouse cursor would “wrap” to the opposite edge. It was like the ultimate non-Fitt’s law configuration. I hated it when I tried it, I would lose the cursor and not be able to find it.

[radiorental]

Just to be pedantic, while somewhat related, that's not Fitts Law.

Fitts Law is specifically about targeting.

The 'feature' to wrap the pointer may compound targeting issues but it's secondary. Again, Fitts' is about distance to and size of a target.

[todd8]

You’re right. What I discovered was that I would lose the mouse cursor because I couldn’t quickly move it to an edge without tracking it visually all the way to begin with and once the cursor crosses the edge it breaks visual continuity by jumping to the opposite side. Today’s multimonitor configurations have the same problem to some extent because they have so much area with small discontinuities at the edge where the cursor jumps to a different monitor.