There is a pile of white snow.
There is a pile of sand.
Snow cannot be sand simultaneously.
exists p1 x1 s1 x2 x3.((x1 = x2) & of(x2,x3) & n_snow(x3) & a_white(s1) & Theme(s1,x3) & n_pile(x2))
exists p1 x1 x2 x3.((x1 = x2) & of(x2,x3) & n_sand(x3) & n_pile(x2))