Using the point B and the point I, construct a line s_b (rule W02);

% DET: points B and I are not the same

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

% NDG: points B and O are not the same

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

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

% DET: points B and N_b must be different

Using the point I and the point N_b, construct a circle k(N_b,A) (rule W06);

% NDG: points I and N_b are not the same

Using the circle k(O,C) and the circle k(N_b,A), construct a point C and a point A (rule W07);

% NDG: circles k(O,C) and k(N_b,A) intersect

% DET: circles k(O,C) and k(N_b,A) are not the same