Lego bricks and Duplo

We have normal Lego bricks (for 4+ years old) and Duplo bricks (for 1.5+ years old).

Quite a sometimes ago, my little girl F came out an idea that using both types of bricks together. I was puzzled whether it will be working since the size are different.

But she managed to put both sizes of bricks together (only limits to one type of normal brick size).

It is such a good exercise for her fine motor skills.