Using the point H_a and the point M_b, construct a circle k(M_b,C) (rule W06);

% NDG: points H_a and M_b are not the same

Using the point H_a and the point M_c, construct a circle k(M_c,A) (rule W06);

% NDG: points H_a and M_c are not the same

Using the circle k(M_b,C), the circle k(M_c,A), the point H_a, the point M_b and the point M_c, construct a point A (rule W08);

% NDG: circles k(M_b,C) and k(M_c,A) intersect

% DET: circles k(M_b,C) and k(M_c,A) are not the same points H_a and A must be different

Using the point A and the point M_b, construct a point C (rule W01);

Using the point M_c and the point A, construct a point B (rule W01);