An illustration of an infinite set of G-minimal AVG extensions. (A) G. (B) G with an added single copy of the repeating unit in bold. (C) G with the added terminal elements in bold. (D) A G-minimal AVG extension with 2 copies of the repeat subunit and the terminal elements that attach w2 and y2. Vertices are identified by lowercase letters, with superscripts used to denote distinct copies of elements in the repeating subunit.