A man wearing all black writing on a piece of paper.
a man is writing a letter
The man is writing on a piece of paper but that doesn't necessarily mean that he is writing a letter.
exists x1 x2.(a_topic(x1) & all x3 s1.((n_writing(x3) & a_black(s1) & Theme(s1,x3)) -> exists e1 x4 x5.(Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & on(x3,x4) & of(x4,x5) & n_paper(x5) & n_piece(x4))) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_write(e1) & n_letter(x2) & n_man(x1))