Stylized lighting shader

I’m trying to make a post processing effect that will get the shape of any light source and make it 2D, then i want it to duplicate a couple of times, size up for each iteration, and I want the opacity to decrease for each iteration as well, then I want to layer it on top of the light source, and have it stay in the same position on the light source. This is probably very complicated to make, but I don’t know where to start and I was wondering if anyone could help?

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