It is early morning at Namera Primary School, in the countryside outside Blantyre. The school perches on an outcrop part way down a steep hillside between a mountain ridge and the plain below. The school yard is lit up in splashes of yellow sunlight. Some children are already gathered noisily here, while others make their way carefully up or down the hillside from nearby villages. This morning is special — every child carries with them a bundle of long grass stems, creating a moving sea of grass that sways above the heads of its small bearers.