MYSTERIES OF THE EQUILATERAL TRIANGLE - HIKARI Ltd

Applications 97
Figure 3.27: Ultrasonic Anemometer [317]
in Figure 3.27, have no moving parts. Instead, they employ bi-directional
ultrasonic transducers which act as both acoustic transmitters and acoustic
receivers. They work on the principle that, when sound travels against/with
the wind, the total transit time is increased/reduced by an amount dependent
upon the wind speed [317].
Application 28 (Natural Equilateral Triangles). Mother Nature has an
apparent fondness for equilateral triangles which is in evidence in Figure 3.28,
where its manifestation in both (a) the nonliving and (b) the living worlds is
on prominent display [54]. (See Appendix A for many more examples.)
Application 29 (Equilateral Triangular Maps). In 1913, B. J. S. Cahill
of Oakland, California patented his butterfly map which is shown in Figure
3.29(a) [132].
It is obtained by inscribing a regular octahedron in the Earth and then
employing gnomonic projection, i.e. projection from the globe’s center, onto
its eight equilateral triangular faces [132]. However, with the highest face
count (20) amongst regular polyhedra, the icosahedron has long been a favorite
among cartographers. In 1943, distinguished Yale economist Irving
Fisher published his Likeaglobe map which is shown in Figure 3.29(b). It
is the product of gnomonic projection of the world to the twenty equilateral
triangular faces of an inscribed icosahedron [132]. In 1954, R. Buckminster
Fuller patented his Dymaxion Skyocean Projection World Map [113] which is