Venkatesh Rao@vgr·Aug 10, 2020TIL about ulexite, “tv rock” natural mineral that acts like optic fiberen.wikipedia.orgUlexite - Wikipedia1215
Venkatesh Rao@vgr·Aug 10, 2020You can buy some on amazon for $10 https://amazon.com/Copernicus-CCTV-TV-Rock-Ulexite/dp/B002FPF9H2…211
Nick Pinkston @NickPinkston·Aug 10, 2020Replying to @vgrThey've also made the concrete block version of this117