Figure 1.

(Left) The eight distinct possible configurations that upon expansion give highly distorted hexagons that are discarded in our generation of GDY-like layers. A and B indicate non-equivalent sides of the hexagon units: B should be considered as a true CC bond, while A represents the diacetylene unit (C₄) of four sp carbon atoms. The configurations are shown as “dual” couples, that is, reversing the role of A vs B. Two couples do not generate a new configuration, for example, BBBAAA = AAABBB. (Right) Four configurations that upon expansion gave undistorted six-sided polygons. The value in the square bracket is the total number of carbon atoms in the ring that uniquely define each building block, h = [6], H = [30]; L = [14]; T = [18], and R = [22]. Line (L) and rhombus (R) blocks are “dual”, so for each layer containing them, we can substitute each L with an R without significant distortions. The definition proposed here follows the one reported in the work by Park et al.¹⁷