I'm a geometry nodes newbie but love the coding/puzzle aspect of it alongside how powerful it can be.
I'm hoping to be able to take a spiral, and extend certain vertices to create new shapes. then be able to convert it to mesh etc.

So i did this in simple blender mode. Added spiral, grabbed some vertices and then extruded etc.
What i think i should be able to do is start with a sinlge vertex (e.g. the right hand vertex), extrude it set direction, then merge into a spiral. As bonus, subdivide the "straight line" part and extrude a branch at a certain angle.
For final piece i'm hoping to animate these spirals "growing out"
I think it must be achievable, but i'm not too sure how from a shape you can extract information and then manipulate individual vertices.
Any help would be great.
R
UPDATE: So looking at the advice below i've created a spiral and got these nodes. Spiral node --> Curve to mesh to get the original spiral. I've then extruded the final vector using Index and COmpare as suggested. However, it's now extruding along normal.
Any ideas how i can change the angle of extrusion?

