https://www.gettyimages.ca/detail/news-photo/painting-demonstrating-the-use-of-a-merkhet-an-ancient-news-photo/90731371
https://www.sav.sk/journals/uploads/073012435_Magdolen.pdf
http://www.setterfield.org/Dodwell_Manuscript_8.html
http://archaeopoject.pbworks.com/w/file/fetch/46946175/MIsler%252520ancient%252520directions.pdf
http://wiki.dtonline.org/index.php/Ancient_Egyptian_Sundials#Description
http://members.aon.at/sundials/berlin-egypte.htm
https://www.wikihow.com/Make-a-Sundial
measuring movement of earth: https://www.education.com/science-fair/article/true-sun-sun-appears-move/
make a sundial for any particular wall or window: https://www.sundialzone.com/en/sundial
universal ring sundial: http://leewm.freeshell.org/origami/ringdial.pdf
another type of sundial: http://www.arvindguptatoys.com/toys/Makeyourownsundial.html
printable sky map: http://www.skymaps.com/downloads.html
make your own planisphere: https://in-the-sky.org/planisphere/index.php
