A basic task for women and girls is to grind the sorghum or maize staple grain into flour.  They prefer to do this on a grindstone with a rough surface.  As the surface wears down it has to be roughened again, which is done by striking it all over with a sharp-edged stone such as quartz.  This produces a pock-marked surface.  The tap-tap-tapping sound is often heard across the village.  Here a baby is beginning to join in the work and adding to the rhythm.