2D vector rotation in material

I want to rotate a bunch of shapes in a texture, where they have an XY gradient in each so that they point towards an arbitrary point in 2D space. Does anyone know how I achieve this? I get the feeling atan2 is involved. If it helps, the blue and alpha channel can contain a solid color in each shape of its center in UV space.
I’ve attached a before and after, where they point towards the center (for example).

Unsure if you want to simulate them rotating in 3D space, but it looks like you just manually rotated them clockwise or counter-clockwise.

If that’s what you’re after, you can use the CustomRotator node and plug it into the texture UV.

No I want them to point to an arbitrary position in 2d space.