A current I flows in a semi-infinite straight wire along y = 2b, z = 0 from very large positive values of x to the point (0,2b,0),
then around a semicircular wire centered upon (0,b,0) and in negative values of x in the z = 0 plane to the point (0,0,0),
then along a second semi-infinite straight wire along y = 0, z = 0 from the point (0,0,0) to very large positive values of x.
Find the magnetic field produced at the point (0,b,0). What are their individual directions?