Did a specific person dream up the "Atheist Atom"?

Certainly not! It was the product of random graphic mutations and selective pressures in competition with other logos.

Atom and Eve came up with it.

Their website doesn’t credit any one person with the design; I would guess it was designed by a committee, or that they commissioned it from someone.

Re. being an “accepted symbol”, it’s a symbol for American Atheists (the non-profit group), but obviously, that group doesn’t represent all atheists, or even all American atheists.

@dappled_leaves

Whatever, it’s good enough for the atheistic dead at Arlington.

@josie

It’s good enough for some. An atheist who does not align with that group may not chose to use it. I certainly wouldn’t. Just as there isn’t one single symbol to represent all Christians buried in US military cemeteries (I know, something other than a 1-represents-everyone policy must be hard to imagine).