A local person is selling a Time Soldier's arcade, it has a "Rotary joystick", I have never run into those, and am not sure if they still have 4 way controls + twisting action, or what exactly they are.
The
LS-30 is an 8-way stick with a 12-position rotary switch.
In rotary joysick games, the 8-way part works like any other 8-way stick and the 12-position rotary switch is used to aim by turning the stick. (shown at 0:30 in the video)
This allows you to move in one direction while firing in another.
To use the rotary function with MAME, you'll need a
rotary encoder.
Scott