Why have I never before seen this quote, cited (as I find on Google) by a wide variety of highly reputed maker-friendly organizations?
He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.
Found in an interview with Sanjoy Mahajan, author of Street-Fighting Mathematics: The Art of Educated Guessing and Opportunistic Problem Solving, on the Freakonomics blog.