So a series of ploughings run down a field leaves a row of sods partly in the furrows and partly on the ground lifted earlier. Visually, across the rows, there is the land on the left, a furrow (half the width of the removed strip of soil) and the removed strip almost upside-down lying on about half of the previous strip of inverted soil, and so on across the field. Each layer of soil and the gutter it came from forms a classic furrow.