The United States of America are divided into two parts. So can we explain that further? Let us draw a NS-axis accurately in the middle.
The contrast becomes clear with a single line. But the upper horizontal line is important. It spans exactly 60°. And the two corners are those of two hubs of the convection cell system. So here is the position of the USA:
The path of the convection lines forms hubs where upper and lower cells meet with each other. So the coasts are actually found to lean to those two points. Just to show how detailed this marvelous coherence between the continent of America and the convection cells underneath is, have a look at this map:
This is how the North American continent is divided into two, or perhaps a few, parts.
Probably someone does not understand the meaning of the lines drawn. The basics: A pair of parallel lines shows the location of one convection roll. There are two layers of convection rolls between 120-410 km depth. Below that, there are large convection rolls, marked with wider lines.