Functions

And yes, I'm aware that x(t) and y(t) are one to one functions of t, but many curves are like that and not considered "functions". For example, the unit circle on the xy plane would fail to be a function, yet it has well-known properties and a well-defined parametric representation.

*coughs on a discussion of parametric and polar functions*

In parametric mode

x=cos(t)
y=sin(t)

and you got yourself a function!