I'm not sure how your cat managed it, as the keyboard shortcut to do this is
8 I believe.
However, to put it back to normal, right click anywhere on the desktop, click
view, followed by any option, EG
EDIT: As there has been some interest,
number produces different views when used on any folder, including the Windows Desktop.
- Extra Large Icons
- Large Icons
- Medium Icons
- Small Icons
- List View
Tested working in Windows 10, Windows 8.1 and Windows Servers 2012 and 2016 (Hotkey may vary between editions, as it's reported to be
Alt on Windows Server 2016 TP4 (Simplified Chinese))