A button to select 1,2 or 3
I want to create a button which performs this task:
The button changes the value of the number `a`.
`a` is initially set to 1. Clicking the button changes `a` to 2, clicking again changes `a` to 3. Clicking yet again changes `a` to 1. (I.e, cyclic)
After choosing a number, the function f(x) = sin(a * x) plotted beforehand, will be changed according to the value of the variable `a`.