[johnlk]

Fascinating article. This has inspired me to make a sundial that works inside my NYC apartment. Ideally, there's some reflective device pointed outside and some warping that happens to allow the sundial to work inside.

[yencabulator]

Maybe you can use a window?

https://www.flickr.com/photos/jlcarmichael/albums/7215768048...

[kjkjadksj]

Why not just install one on the outside window sill?