picturing water
Zigzag patterns are strongly rooted in the cultural expression of the ancient Egyptions. Especially matters referring to water were expressed in terms of the zigzag stripes. In the picture beneath the "Great Green Divinity" which is the personification of sea and swamp. On his body zigzag stripes run in horizontal direction.

Usually, however, zigzag stripes picturing water are running in vertical direction as hown in the examples behind the knob beneath.(klick on de knob)