Confirm that each of the combinations of A and B given in the table on p. 393 does indeed give rise to a spectrum with the same lineshape.
Draw up a diagram, similar to that of Fig. 11.6 on page 394, to illustrate that, in a pulse-acquire experiment where the pulse phase goes through the sequence [x, y, -x, -y] and the receiver phase goes through the sequence [-180°, -270°, 0°, -90°], each spectrum has the same lineshape.