English: Circled nodes are the root lattice of Coxeter type A_2. Lines are the reflecting planes of the reflections in the associated affine Coxeter group (the affine symmetric group).
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse
Captions
Type A_2 root lattice with affine reflecting hyperplanes