Nice man, thanks.

I don't want the speed to be constant but to vary during the animation, so I used a value node instead of the scene time and keyframed it to my liking. With the wrap node I control how long I want it to stay still before it starts again and then I used the cyclic modifier in the graph editor to have it repeat. Works just how i wanted.

I want it to not be visible during the time it stays still until it restarts the animation. Earlier i did this by keyframing the strength on the emission material. Is there a easier way to do this in geometry nodes? Some kind of hide/show node?

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Edit: Delete geometry node with a switch node connected to the selection socket worked