Equation for a Vector Field Spiraling to a Point

Question

I'm building a generative animation and one of the things I'm trying to achieve is a vector field that spirals towards a point.

I've discovered f(x,y) = [y-x, -x-y] generates a spiral that converges at the origin:

_{(source: wolframalpha.com)}

https://www.wolframalpha.com/share/clip?f=d41d8cd98f00b204e9800998ecf8427e8rdj53cf6e

Now if I want to achieve the same effect but, move the point of convergence (POC) around how would I do that?

I've tried adding offsets to the x and y functions. Eg: to move the POC to (5,5) I tried f(x,y) = [5+(y-x), 5+(-x-y)] but, it didn't work.

Answer 1

Hint: $f(x,y) = (y-x, -x-y)$ translated is $f(x-5,y-5)$.