What's the difference between superpose and superimpose?

Merriam-Webster has them as synonyms, but the difference is this: consider the Star of David, and consider the construction of one with two solid triangles rather than interlocking triangles.

The two triangles are superimposed, and both are evident.

Were one triangle not rotated, they would be superposed.

They are synonyms but have different scopes of usage.

Superimpose is the term found in general use.

Superpose is used mostly in scientific or mathematical contexts; see 'superposition'.

Superimposed = one image overlying another.

Superposed = the addition of one image to another, e.g. mean water level = 5mOD

Waves = +/- 1m above mean level

Superposed = water level between +4mOD and +6mOD

I am an American mathematician who would have liked to comment on Cornbread Ninja's answer, but I have no experience points and so am giving an "answer" instead. The variability in usage of both terms is so great that extracting a true distinction seems useless. A reading of the OED definition of each has led to me sympathize a little with Cornbread Ninja's answer. But the 'interlacing' of the triangles in Cornbread Ninja's example seems to obfuscate the distinction being described. The distinction is that superimposed triangles have not merged. Superposed triangles would meld together. In physics and mathematics we speak of the `superposition' of waves. For example, light is a superposition of electromagnetic waves at different frequencies. Different frequencies correspond to different colors. The colors meld together and cannot be distinguished (without a prism for example). So superposition makes sense in this context. In contrast, superimposition would be exemplified by placing pieces of colored pieces of construction paper upon one another.