Neuberg Circles
The Neuberg A_1-circle is the locus of the polygon vertex A_1 of a triangle on a given base A_2 A_3 and with a given Brocard angle ω. From the center N_1, the base A_2 A_3 subtends the angle 2ω. The same procedure can be repeated for the other two sides of a triangle resulting in a total of three Neuberg circles. Similarly, three reflected Neuberg circles with centers N_1^, , N_2^, , and N_3^, can be obtained from the main circles by reflection in their respective sides of the triangle.