A simple, straightforward, fun setup in Geometry Nodes, showcasing a creation of a double spiral and converting it into mesh with segmentation in Geometry Nodes.

The Animation Nodes add-on is chosen to create the spiral in the first step, simply because it is more adapted for this specific case. The spiral curve created in AN is called "ANSpiral". It is read and utilized in GeoNodes. (To be clear, you can simply add a spiral node in GeoNodes, and skip AN all together. It is used for added functionality)

(AN is a visual script addon, just like the built-in Geometry nodes. FOR THE BLEND to work, you need it installed ! You dont need to know how to use it, since the node setup is quite self explanatory. You might have to restart Blender after installation. Google "Animation Nodes" and download the addon from its official website.)

The nodes containing the control values are highlighted in red, play around and have fun !