(S (S (BASENP (NNS Tents)) (VP (VBD were) (VP (VP (VBN blown) (PP (IN on) (BASENP (PRPD their) (NNS sides)))) (COMMA ,) (S (VP (VBG becoming) (BASENP (JJ veritable) (NN wind) (NNS sails))))))) (PERIOD .))