Street performer by the beach on stilts playing the tuba.
Someone is playing a musical instrument.
A street performer is someone.  A tuba is a musical instrument.
exists e1 x1 x2 x3 x4 x5 x6.(n_tuba(x6) & n_beach(x3) & a_topic(x1) & by(x1,x3) & on(x3,x4) & Theme(e1,x6) & Actor(e1,x5) & v_play(e1) & (x4 = x5) & n_stilt(x4) & n_performer(x1) & (x1 = x2) & ne_per_street(x2))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_instrument(x2) & a_musical(s1) & Theme(s1,x2) & n_person(x1))