Not quite the same. The OotS comics reference the concept of Elementals that is common in the Fantasy genre (and which I believe comes mostly from Norse mythology... but I'm not certain). This comic references Avatar: The Last Airbender. Both deal with the classical elements, but that doesn't make them the same joke.
Greek, actually. They are the Hellenic elements, though they also map to Tibetan systems.
In terms of form they are almost precisely the same joke. The fact that they are referencing slightly different genres doesn't make it a different joke, it makes it the same joke in a different genre. It doesn't have to have even the same elemental basis
–they could be using the Japanese classical element system (Air, Water, Fire, Earth, Void) and it would still be essentially the same joke.
The form of the joke is:
- Take an "element" system from any classical, mystical, or fantasy system which is used or purported to be used for some set of powers or for a ritual purpose.
- Provide a situation involving the powers, but using the modern element system.
- Show something indicating what that might look like.
For example, this follows the same form and could be turned into the exact same joke:
"I tried being Wiccan, but no coven would accept me after I insisted on calling the watchtowers for each of the 118+ elements."
"Hail ye guardians of the watchtowers of Molybdenum! Guardians of Alloys and followers of Hjelm, I do summon, stir, and call thee up…"
Same joke, slightly different set of inputs.