Using the point M_c and the point G, construct a point C (rule W01);

Using the point H_a and the point C, construct a line a (rule W02);

% DET: points H_a and C 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_c,A), the line a, the point M_c and the point H_a, construct a point B (rule W05);

% NDG: line a and circle k(M_c,A) intersect

% DET: points H_a and B must be different

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