Neon Flicker
X-ray · layers
Parameters
How this effect works
A neon letter is really two lights in one: the bright tube itself and the soft halo it throws on the wall. Here both are drawn with text-shadow — a tight white shadow plays the tube's hot core, and two wide pink shadows play the halo. Turn the glow layer off and you're left with flat letters: the "neon" was never in the font, only in the shadows.
The flicker is a tiny bit of honest randomness. A few times per second we roll a die; when it comes up, one letter "loses power" — for a brief buzz window its brightness snaps randomly between dim and lit every frame, exactly like a failing tube arcing, then it settles back to full. The per-letter layer is what sells the realism: real signs never fail as a whole — one tired tube stutters while the rest hold steady. Switch it off and the whole sign dips together, which reads more like a power cut than a moody bar.