What is the enharmonic equivalent of B sharp?

  You could also call it B double sharp, all are correct but it depends on what context you're playing the note. When you have notes like this that are the same but with different names they are called enharmonic equivalents. Whether you'd call it D flat, C sharp or B double sharp depends on what key you're in.

according to:   Enharmonic Equivalent Notes, Scales, Keys & Intervals | HMThellomusictheory.com › learn › enharmonic-equivalents

this exemplifies - rondo form