"uncle's uncle's brother's son" I'm always confused by familial relations. The diagram seems biased to maternal grandparents (assuming square/circle is boy/gir

"uncle's uncle's brother's son" I'm always confused by familial relations. The diagram seems biased to maternal grandparents (assuming square/circle is boy/girl) - an uncle could also be on the father's side. Also, your "uncle's brother's son" could be you. I'm pretty sure they discussed these alternatives (and probably deliberately chose this very example as an excuse to do so.)