Homemade tree swing

Last week Katherine decided she was going to make a swing for the tree in our yard. At first I thought her plan was to make a little swing for her dolls, or maybe the fairies in the fairy house, but as she started gathering materials it became obvious she was going to build herself a swing. We're used to her making whatever it is that she wants but doesn't have - skis, scooters, a violin, flip flops. She usually fashions these things out of cardboard, paper, string, and tape. I assumed this swing would end up like that - kind of real, but mostly pretend. But half an hour later, we peeked in on her project and found this:

I'm not so sure about that middle rope, and Dave did check the knots later that night, but it appears to be sound. They love it and have already spent hours swinging on it. 

This swing reminds me that the less I am involved in their play, the more creative and resourceful they are.