MICRO SHADOWS

ISBN  0-9765286-7-3

a
very short book, uses microShadows.xls  

and the book and ITS spreadsheets are
in ZIP form  

but, for a
smartphone here is the book

Build A Horizontal Sun Dial.    A 14 page booklet on build
then fix a horizontal dial. Shows how to stuff, but no
theory.   

If you like it, try SIMPLE SHADOWS or better still buy
Illustrating Time's Shadow
Micro Shadows is as simple as it gets,
if you want more, download Simple
Shadows