Ninja training

I’m at the building site of a house. The wood frame has recently been walled by plywood. I walk up and start to talk to a small group of boys sitting up on a beam of wood. They sit almost level to my chest as I stand there. And they have been playing with triangles of scrap wood about the size of saucers. There game consists of throwing them against the wall behind me like throwing stars. Their scraps of wood fly into the plywood and dig in like a knife. There are even splinters of wood from the wall projecting around them. One of boys tries to run off as I talk but I sit him back down and borrow his triangle of wood. I throw it at the wall and it bounces harmlessly off.