Sorry to jump in so late, but this is actually old artwork from the original 99designs contest. This was the winning mock-up, which appears to have been tweaked since to give the current logo. You can see more here - this competition wrapped up around three years ago.
It feels a little confusing to present this back to the current community with no explanation, particularly since the image of Gridcoin has actually moved away from this quite ostentatious representation since the contest ended.
For what it's worth - I also took a look at the detailed brief for this contest when starting the design process, as well as what was popular and not so popular last time, to better inform the process this time around.
Great find! Makes sense