Mouse cursor shows a flickering, square matrix

20 inch iMac, mid-late 2000s

Mac OS X v10.9.1

Magic Mouse

Mouse cursor shows a flickering matrix that starts at the mouse cursor and then flows down and to the right. Flickering matrix is about 1 inch by 1 inch and resembles a 8x8 matrix with short lines that are not connected.

Troubleshooting completed:

- Rebooted computer

- If the mouse cursor size is incresed in the Accessibility section of the System Preferences, the flickering matrix temporary goes away.

- Same issue with Magic Mouse and Dell wired mouse

- Logged in to another admin account, no change

- Reset PRAM, no change

- If the entire screen is zoomed in at all, the flickering matrix goes away