Using the point A and the point T_b, construct a line b (rule W02);

% DET: points A and T_b are not the same

Using the point T_a and the line b, construct a circle k(T_a,foot[T_a,c]) (rule W11);

% NDG: point T_a is not incident to the line b

Using the circle k(T_a,foot[T_a,c]), the point A, the point T_a and the line b, construct a line c (rule W13);

% NDG: point A is outside the circle k(T_a,foot[T_a,c])

Using the point T_b and the line c, construct a circle k(T_b,foot[T_b,c]) (rule W11);

% NDG: point T_b is not incident to the line c

Using the circle k(T_b,foot[T_b,c]), the point T_a and the point T_b, construct a line a1 and a line a (rule W12);

% NDG: point T_a is outside the circle k(T_b,foot[T_b,c])

Using the line a and the line b, construct a point C (rule W03);

% NDG: lines a and b are not parallel

% DET: lines a and b are not the same

Using the line c and the line a, construct a point B (rule W03);

% NDG: lines c and a are not parallel

% DET: lines c and a are not the same