After school yesterday we had a play date with one of Liam's best friends, B, who doesn't go to 'our' school, but goes to one nearby, and two other mutual friends (twins) who used to go to B's school but now goes to Liam's.
The kindergarten playgrounds are enclosed, but the class one & two playground is out in the open, so we sometimes go down there after school finishes for a play, and that's what we did.
The boys (and one girl, B's four-year-old sister) played really well together, for over two hours. By the time we finally dragged them away it was getting dark and I had to call Chris to warn him that he'd be home before us, and could he please get something out of the freezer for dinner.
They played with sticks and logs and rocks and dirk (mud, really) building a 'dam' below a pond that the class-two children had built during the day. They filled it with bore water from a tap, using a big saucepan they found in the sandpit. It did leak a bit, but overall I have to say they did an amazing job, working together with virtually no supervision (their mum's being busy talking and supervising the toddlers), and no noticeable conflict.
One of the things their mum's were talking about was the importance of free play. B's mum, S, (one of my S friends) was telling us some recent research she'd heard about, that found that at this age free play is the most important factor in developing intellect. And as we watched them 'working' none of us found that at all surprising. S's kids don't go to the Steiner school (though she's torn about it), but since free play is what they are doing a good 80% of the time in the Steiner kindy, the other two of us were able to feel quite smug.