Circle of 5ths
I use it for simple improvisation and scale practice in lessons. However there are many more keyboard musicianship skills that can be utilized with this visual aid… the clock concept just helps your student establish and reiterate your teaching visually!
This sharpens the mind of astute students, it is great for improvisation skills, figured bass and general keyboard musicianship.
Major and Minor Scale Ladder
They also help you see how your student is processing the theory of the scale formulas rather than relying on rote and/or muscle memory.
Tone-Semitone Step Ladder
A great visual aid used in conjunction with your instrument and you will be surprised how quickly they will be playing the most difficult of scales!