robmck wrote:

Just a random curiosity: Can you use a typeball for a Selectric Composer on a monospacing Selectric (I/II, or III)? Sure the spacing will be all wrong, but are the letters where they are supposed to be?
 

IBM Composer elements might fit in a Selectric but they will not work as intended.  The letters on the element are in different spots so the letter corresponding to the key pressed will not be the letter that appears.