The drummer, who is wearing white, is laughing.
A cellist looking smug.
A drummer and a cellist are two different types of musicians.  One cannot look smug while laughing.
exists e2 e1 p1 x1 x2.(n_drummer(x1) & Actor(e2,x1) & v_laugh(e2) & exists s1.(Theme(s1,x2) & a_white(s1)) & Topic(e1,p1) & Actor(e1,x2) & v_wear(e1) & (x1 = x2))
exists e1 x1 x2.(a_topic(x1) & n_smug(x1) & Actor(e1,x1) & v_look(e1) & of(x1,x2) & n_cellist(x2))