Let A1 be the point in the circumcircle where AA1 is parallel to BC, A’1 the intersection of the circumcircle with the parallel from A1 to the A-altitude. Define analogously B1, B’1, C1, C’1. The circles {OA1A’1}, {OB1B’1}, {OC1C’1} concur at a point in the Euler line.