It has been mentioned that triangle ADE is isosceles. But it is not any ordinary isosceles triangle. This triangle is the cross-section of a tetrahedron, the simplest Platonic solid, which is made of four sides, each an equilateral triangle.

If a tetrahedron is circumscribed within a sphere (figure 24), where one apex of the tetrahedron is located at a pole, the remaining apexes will touch at 19.5 degrees from the equator. It is interesting how most planets in our solar system display phenomena at this latitude. For example,

Earth – Hawaiian Mauna Kea Volcano, 19.6
degrees N

Mars – Olympus Mons Volcano 19.3 degrees
N

Jupitor – The Great Red Spot, about 19.5
degrees S

Neptune – The Dark Spot, about 19.5 degrees

Another astonishing fact is that the D&M Pyramid and Olympus Mons are 120 degrees apart, as if marking two apexes of the tetrahedron on the sphere of Mars.

Perched atop the crater wall, on the side
opposite the Cliff, is an obviously three-sided pyramid-like projection,
possibly a tetrahedron (figure 23). Its appearance, like the Cliff, again
raises the questions of later origins because of the lack of blast shadow
or signs of impact damage. This object has been called the Tetrahedral
Pyramid. (There is another similar Crater Pyramid located 480 miles northeast
of Cydonia.) The Cliff-Tholus-Tetrahedral Pyramid arrangement forms a 19.5
degree angle. This “tetrahedral latitude” of 19.5 degrees appears six times
in three distinct contexts: The D&M Pyramid, the Tholus-Cliff combination,
and the City Square-Face-D&M “benchmark” pattern (McDaniel 1994).

Fig. 23 Tetrahedral Pyramid (Hoagland/Drasin) The Tholus-Tetrahedral Pyramid line lies north/south. |
Fig. 24 Circumscribed Tetrahedron (Hoagland) |