On a trip to New York for the weekend to visit my sister, Jessica (nearly 3) was playing with some wooden trains.

She held one up. "These ones are subway trains." (No surprise; she'd been impressed with our trip on the subway earlier that day.)

"The yellow ones are subway trains?" my sister asked, clarifying.

Jessica paused. "I will check on my phone." Her empty hand suddenly grasped an imaginary phone. With her other finger she touched it once or twice, then she just looked at it. "Yeah, yellow ones are subway trains."

Her Mommy, Daddy, Aunt and Uncle all use iPhones. She's apparently observed some things about how we use them.