[Perhaps if Luke finds himself wandering about the village today, he might encounter a familiar face sitting on one of the benches. Someone who hasn't been showing up for stable duties, in fact.]

Let's see. If there's a mother and a father, then couldn't they be someone else's son and daughter too... [Beat.] Wait, that can't be right.

[His journal is right beside him. Wouldn't you know it, he's trying to solve your puzzle right now.]