Proposition: Prop. 9.32: Power of Two is EvenTimes Even Only
(Proposition 32 from Book 9 of Euclid's “Elements”)
Each of the numbers (which is continually) doubled, (starting) from a dyad, is an eventimeseven (number) only.
 For let any multitude of numbers whatsoever, $B$, $C$, $D$, have been (continually) doubled, (starting) from the dyad $A$.
 I say that $B$, $C$, $D$ are eventimeseven (numbers) only.
Modern Formulation
(not yet contributed)
Table of Contents
Proofs: 1
Thank you to the contributors under CC BYSA 4.0!
 Github:

 nonGithub:
 @Fitzpatrick
References
Adapted from (subject to copyright, with kind permission)
 Fitzpatrick, Richard: Euclid's "Elements of Geometry"
Adapted from CC BYSA 3.0 Sources:
 Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016