Geometry Nodes: Bend Modifier

Hi,
I am looking for a tutorial i had found a while ago for bending geometry similar to simple deforms bend.

The guy made a mesh line and then used math (sin, cos a bunch of other stuff) to bend the line.

Basically you use math to calculate circles around the center and the further the vertex is from the center the further along the circle the vertex will be placed.

I believe it works the same as it does in higgsas bend node but the tutrial also explained how the math works exactly.
(Higgsas) Geometry Nodes Groups Blender 3.1/3.0

So does anybody happen to know what I am talking about and can point me to the tutorial in question?