A man in a black shirt playing piano.
A lady is playing the violin.
It can either be a man or a lady.  They are either playing a piano or playing the violin.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_piano(x4) & (x2 = x3) & n_shirt(x2) & a_black(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1 x2.(n_violin(x2) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_lady(x1))