Not mine, daycare kid in an at home daycare I helped out for a while.

Kid's about 15 months old, can walk, speaks in two word sentences. Cute as a button. The daycare has a couple of rules. Toys from the daycare are for everyone's use, but one child has to wait until the other has finished playing before taking a toy. If a child brings a toy from home (not a daily occurence), other children have to ask if they are allowed to play with it. In general, those rules work quite well, if gently enforced.
One day, this particular kid comes up with a trick: She waits until a second kid has picked up the toy another kid has brought from home, walks up to the second kid, tells them 'that's (other kid's name)'s!', when the second kid drops the toy she takes it for her and plays with it without having to ask the owner.