You can do the same thing by showing the parameter lines for constant t-values. These are straight lines.
So we now clearly recognise the two sets of straight lines on this HP surface (hyperbolic paraboloid), which is therefore a two-fold ruled surface.
Paraboloid - Wikipedia
Ruled surface - Wikipedia

BTW. the equation of this surface in kartesian coordinates is z(x,y):=x*y.
This said you could also parametrise this surface that way:

But, at the risk of repeating myself, this HP surface is just one of an infinite number of possible surfaces... 😉
Here is a last one, a cone:
