Generally speaking you can do a lot by doing arithmetic with an input parameter.
Easy first example: drawRectangle(size)
Where you choose whether size means the short or long side. Then in the code you'd have something like
Getting bigger, rather than treating
size as a straight pixel value, treat it as a scaler for the size of something. Have it be a value between 0-100 or a decimal between 0.0 and 1.0 that represents the % size of a thing.
If you do arithmetic on parameters, plus think about using parameters as inputs to other functions, the world opens up a bit.
Not sure if that helps.