… For obvious reasons, three of anything, is traditionally depicted as a triangle…
Not withstanding our preoccupation with purely symbolic notions of dimension the triangle of number appears to have a base of points one and two and a peak of point three.
Put simply, this is because the qualities of points one and two reflect, and are summed in point three.
As this is an accumulative process it may be as well to move clockwise around the triangle.
Triangle of Number
to be continued
Source: Stuart France