Using the point O and the point M_b, construct a line m_b (rule W02);

% DET: points O and M_b are not the same

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 M_b and the line m_b, construct a line b (rule W10a);

Using the circle k(M_b,C) and the line b, construct a point C and a point A (rule W04);

% NDG: line b and circle k(M_b,C) intersect

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 C and the point O, construct a circle k(O,C) (rule W06);

% NDG: points C and O are not the same

Using the circle k(O,C), the line a, the point O and the point C, construct a point B (rule W05);

% NDG: line a and circle k(O,C) intersect

% DET: points C and B must be different