The "clover leaf" and "beach ball" cursors are from the Mac OS. The hour glass is on Windows systems.
If you look carefully, you actually get the Clover Leaf and the Period when a script is running and these are the keys you can use to abort the script on a Mac--press both the command and period keys.
If you look carefully on a windows system under the same circumstances, you may see the hour glass in combination with the Esc key. This is telling you that you can abort the script by pressing the Escape key.
The beach ball and Hourglass without Esc indicators are telling you that you have to wait for whatever process is executing to complete, but that its not a process you can abort with anything short of a force quit action.
I see the hourglass on MacOS. On occasion.
I should have mentioned I am running a Mac.
A humorous history of wait cursors.
The amount of free RAM can be monitored by keeping Activity Monitor (utiliities folder) in the Dock set to display RAM Pie Chart.
If the green (free) RAM disappears, you are more likely to see a BSOD. (RAM contents are being written to a hard drive, oftentimes.)
You can check on possible RAM upgrades at Crucial.com, knowing the speed of your processor (About This Mac) is required.