These are tiny, super-strong magnets, Buckyballs, the type one is cautioned not to swallow. The ex, who somewhat fancied himself Fuller’s unrecognized heir, bought them. Now that the kids are in their teens and understand what they can do inside one’s body, they’re relatively safe; they mostly live on the fridge. The Little Prince in particular loves them; he associates them with the good parts of having his father around.
So much (personal, family) history in this one photo. Especially in the gap.