Using the point A and the point I, construct a line s_a (rule W02);

% DET: points A and I are not the same

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

% NDG: points A and O are not the same

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

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

% DET: points A and N_a must be different

Using the point I and the point N_a, construct a circle k(N_a,C) (rule W06);

% NDG: points I and N_a are not the same

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

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

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