Casio CT-S500 could have been a great looper. The developers really went to great lengths to make sure it can not be used as a looper. At the same time, it's obvious that it can loop by the way stock rhythms 1 through 243 loop. The things in the category of songs do not loop: 11. ToneRec, 12. RhythmRec, 13 through 17 MultiTrkRec and 1 through 10 UserSong all could have been useful if they looped. But they are almost useless.
The tempo can not be changed on any of the recordings (previously listed) 11, 12, 13-17, and UserSongs. We can change it live, and it stays while the power is on. We can not save the tempo change.
Everything is in there to create UserSong(s) 1 through 10 and User Rhythms 244 through 293, but the system is intentionally designed to prohibit using CT-s500 from doing so. You can't even copy a UserSong to another UserSong without using a USB drive. You can't copy anything recorded onboard to any of the UserSong(s). You can't create anything at all onboard the CT-S500 and store it in a User Rhythm (244-293). Even if you do import user songs with a USB drive, none of these user songs loop. A user can only import user rhythms that loop, but we have to find previously created ones or use a computer, extra software, some other music creation app or daw and read a 36 page document to do so.
If there was a category of keyboard called "anti-arranger", Casio CT-S500 would be one of those.