[smolder]

Yeah, it's something best planned with construction, and a bit pricey, but worth keeping in mind for anyone who intends to build a bunker. :)

Also not bad for high efficiency net zero type homes to supplement natural light without too many windows compromising the thermal envelope. I personally like the variability of natural light for how it keeps you connected to the outdoors. You know when a cloud is overhead or the sun is rising or setting. I've simulated sunset and sunrise with LEDs through color temp and timing but I've always wanted to experience the solar fiber type.