Euler’s circle : In geometry, the nine-point circle is a circle that can be constructed for any given triangle. It is so named because it passes through nine significant concyclic points defined from the triangle. These nine points are:
- The midpoint of each side of the triangle
- The foot of each altitude
- The midpoint of the line segment from each vertex of the triangle to the orthocenter (where the three altitudes meet; these line segments lie on their respective altitudes).
The nine-point circle is also known as Feuerbach’s circle, Euler’s circle, Terquem’s circle, the six-points circle, the twelve-points circle, the n-point circle, themedioscribed circle, the mid circle or the circum-midcircle (wikipédia)
I find signs everywhere… I see that 9 in an inverted 6, it is the symbol of the end AND of the beginning… And my story begin in 1969, etc.