You see what's an end-less mirror?
wait, looks like the lights inside are there, did you make each one?
Yes and no, I've made all the ones which looks the highest, and the others are reflexions of an end-less mirror.
huh, how do you made an end-less mirror?
With two opposite one-way mirror or one mirror and one one-way mirror. And in blender, you need to connect a glass shader and a glossy shader to a mix shader with an input Geometry backfacing to the fac of said mix shader. Oh, and you also need to change the light path in the render menu. So "integrator preset" -> "full global illumination" and change the number of min and max bounces (personnally I take 50 in min). If you don't, the number of reflections will be limitated.
I love it. If you use some LEDs, a double sided mirror, and two one way mirrors you could actually make this a reality.