An analog signal is a continuous signal; analog signal values are known for all moments in time.
A digital signal is a discrete signal; digital signals are known at certain specific times.
how audio works
how film works = https://www.youtube.com/watch?v=rqSbmw9u1CE&feature=youtu.be&t=127
lossy example = https://www.youtube.com/watch?v=icruGcSsPp0
how stereo records work = https://www.vinylrecorder.com/stereo.html
Synchronism No. 6 = https://www.youtube.com/watch?v=UNcVjQUZ5VI
Tristan Perish 1-bit Symphony = https://vimeo.com/12244413
Andrew May Ripped Up Maps = http://andrewmaymusic.com/Works/Ripped-Up_Maps.html
a transition from a land to a pit or a pit to a land is interpreted as "1" while the absence of a transition is interpreted as "0"