Bundles upon bundles

"The usual bypasser is a woman sauntering slowly down the road with bundles upon bundles balanced on her head. These women are pillars of wonder, defying gravity while wearing the ho-hum aspect of perfect tedium. They can sit, stand, talk, shake a stick at a drunk man, reach around their backs to fetch forth a baby to nurse, all without dropping their piled-high bundles upon bundles. They are like ballet dancers entirely unaware they are on stage. I cannot take my eyes from them." (Barbara Kingsolver, "The Poisonwood Bible")