I noticed this idiosyncrasy one day when I was skyping with my Mom.
Claire was taking turns playing with her Little People firetruck and looking out the window and talking to Grandma and typing on her laptop. Fairly normal for a one-year-old.
My mom and I were just chatting away when we both, almost simultaneously, noticed that Grace had spent the last 15 minutes doing the following:
1. Taking the blocks out of their container and tossing the blocks around the room.
2. Gathering all of the blocks.
3. Putting the blocks back in their container.
And she repeated this process for 15 MINUTES! I've never seen a one-year-old with that kind of attention span. She must have tossed them out/picked them up more than a dozen times.
She never got distracted. Never moved on to something else. Just completely zoned in on her block collecting.
Ok, so she did get distracted at one point.
Yes, Claire, we see you have her block. You'll make a great thief one day.