CAUTION! ALERT! ACHTUNG!
Hey look, here's a thing you should pay attention to. How do you know you are supposed to pay attention? I used all caps and made a reference to a U2 Album, but this is the Internet. How would you know in real life? I could yell at you a lot, but I would get tired and might need a bathroom break, and you might not be able to hear me. Well, you'd probably end up falling down a well with out a proper warning. I could paint a big sign that says "WATCH FOR FALLING ROCKS!" in Comic Sans, that would really get your attention, until it got dark. If I painted a sign, attached lights, and a siren then you would surely know that Anvils may be dropped from hot air balloons.
But this is the real world, where you don't paint big signs and lights and sirens cost money and annoy the neighbors. You want a cost effective solution that will catch people's attention day or night and have I got a deal for you. Reflective Glow in the Dark Tape. Sure you may have had reflective tape attached to your hindquarters as a young child on Halloween and I really enjoyed my knock-off glow in the dark light sword (some kids had battery powered Lightsabers) but this is modern technology.
If there is light around or a light source it'll reflect white back at your eye sockets. If there isn't immediate light it'll glow in the dark and glow bright green back at your eye sockets. Are you sold yet? No? Let me try a pitch they use on TV, I'll shout buzzwords and key-phrases at you. LIGHTWEIGHT. FLEXIBLE. RECYCLABLE. MADE IN THE U.S.A. Now get out there and cover your world in reflective glow in the dark tape. You don't want any accidents on your watch.