The classic "Let's Pretend We're Pregnant" photography pose.

So, here's the story: this pregnant woman and her husband thought it would be a fun idea to pretend that they were taking still photos with the woman's father, while they're really shooting video. The plan was to slide in a few clues about the baby-to-be and capture the moment when the guy figured out that he was gonna be a grandfather.

The first hint is subtle, and it goes right over his head. The next is less so, but dad is far too busy laughing and having fun to do the math, so he misses that one, too. Next comes a kind of obvious one; he doesn't catch it. Eventually, they just flat out tell him. Somehow, that doesn't work either:

Sources: Brandt Dary | h/t redditor 123CJP