premise: A person on a bike is midair, twisting his body around the handlebars, with graffiti behind him.
hypothesis: A person is performing tricks in front of a crowd.
explanation_1: The person on the bike is not necessarily preforming tricks. There is no mention that he is in front of a crowd.
explanation_2: There may not be a crowd and he may not be performing in front of them.
explanation_3: There isn't any mention of a crowd, onlookers or other people in the first sentence.
premise_logic: exists e1 p1 x1 x2 x3 x4 x5.(n_male(x4) & n_handlebars(x4) & for(p1,e1) & with(e1,x5) & behind(x5,x4) & n_graffitus(x5) & around(e1,x4) & Theme(e1,x3) & Actor(e1,x1) & v_twist(e1) & n_body(x3) & of(x3,x1) & n_male(x1) & exists x6.((x1 = x6) & n_midair(x6)) & on(x1,x2) & n_bike(x2) & n_person(x1))
hypothesis_logic: exists e1 x1 x2 x3 x4.(in(e1,x3) & of(x3,x4) & n_crowd(x4) & n_front(x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_trick(x2) & n_person(x1))