Not sure exactly what the two morphisms "are" in **Puzzle 168** but I just noticed this which may or may not help:
$$\alpha_{a',b'}(g \circ h \circ F(f)) : a' \rightarrow G(b')$$
and
$$G(g) \circ \alpha_{a,b}(h) \circ f : a' \rightarrow a \rightarrow G(b) \rightarrow G(b')$$
The naturality square essentially went around the world to say these two are equal.
$$\alpha_{a',b'}(g \circ h \circ F(f)) : a' \rightarrow G(b')$$
and
$$G(g) \circ \alpha_{a,b}(h) \circ f : a' \rightarrow a \rightarrow G(b) \rightarrow G(b')$$
The naturality square essentially went around the world to say these two are equal.
Version 2.1.8p2
