This is just a comment about variable names. If you set this project aside and come back to it in a while, you might not remember which button turns what way.

Try to use variable names that mean something:

ButtonL
ButtonR

That way you will know at a glance what to expect in your code. It also makes it easier to others if you work in a team environment, or share your code with others.

(you don't have to do this, it's just to help make things clear)