>>/76726/
 >>/76679/
That Tokyo Freemason coin features Mt Fuji in the center of a perfect circle. OOT, and MM's volcanoes were cartoonish, point in a circle symbolism, just like those coins. The re-occurring volcano symbolizes Vulcan, and Tubal Cain.

This is an interesting article mentioning how Majora's Mask put excess emphasis on color to distinguish the four areas. He mentions the decorative volcano with a ring, and how it adds interest to the scene.

https://games.avclub.com/the-one-weird-trick-nintendo-used-to-pretty-up-the-lege-1798272489

Ocarina Of Time had an art style that was used, arguably well, to distinguish the different areas by giving one color per place. Death Mountain is brown, the forest is green, the lava areas are red, the desert is tan, etc. Majora’s Mask instead based its look on two colors per zone: purple and green for the swamp, white and blue for the mountain, green and blue for the ocean, and brown and orange for the canyon. There’s even clear spots where they changed the color of visuals reused from Ocarina Of Time to give the game more visual distinctiveness.

For example, this section of the swamp features what is clearly the model for Death Mountain, complete with the ring around it. What’s notable is that this volcano-looking spot is never actually visited in the game. It’s just there to give a bit of a different look to the area. It actually is at the Forest Of Mystery, where you lose sight of the purple water for a bit.