The case of a 3-arm interchange is not covered in the article's section. A special constuction can be found at the I-10 / I-20 in west Texas, also applied at some interchange constructions in Florida. This example shows how costs of flyover ramps and bridges are increased, compared to a simple at-grade ramp/road.
Counseling and therapy are generally two synonymous terms as they can be interchanged. A therapist can provide counseling and psychotherapy. However, a person who counsels called a counselor will depend on the degree he or she has received. Therapy involves a more difficult task to do compared to counseling. So the people conducting that can be psychiatrists, psychologists, or social workers.
1 Instead of the behavioral approach adopted by psychologists, a counselor tries to encourage the patient to direct the treatment session.  In a broader sense, both psychologists and counselors are specialists who try to solve personal problems of people though adopting different approaches.