"Tent door" in Phoenician

Down by the mouth of

Egypt’s great Nile, 

Learned Herodotus saw a

Triangular pile of sediment

And called it this with a big Greek smile.

I was at Olympic National Park’s NatureBridge with 6^th graders this past week. The word ‘delta’ came up while we studied water flow and its impact on land. It also means change or difference in mathematics.