By statutory definition, theft is completed when an accused unlawfully appropriates property with intent to deprive the owner of it. See TEX. PENAL CODE ANN. 31.03(a) (Vernon Supp. 2000). For the penal code's purposes, the legislature has defined the word unlawful as conduct that would be criminal or tortious in the absence of some applicable defense. See id. 1.07(a)(48) (Vernon 1994). The code's definition of unlawful applies to each of that word's grammatical variations, such as the variation contained in section 31.03(a), where the word unlawfully is a generic characterization of the methods offenders use to commit the statutory offense of theft ("a person commits theft if he unlawfully appropriates property with intent to deprive the owner of property"). Theft as defined in Section 31.03 constitutes a single offense superseding the separate offenses previously known as theft, theft by false pretext, conversion by a bailee, theft from the person, shoplifting, acquisition of property by threat, swindling, swindling by worthless check, embezzlement, extortion . . . and receiving or concealing stolen property. Id. 31.02 (Vernon 1994). When the evidence shows that a person has attempted to commit theft of property in the context of section 31.03 by issuing or passing a check drawn on a bank in which the person had no account at the time of the offense, that conduct is prima facie evidence of the accused's intent under section 31.03 to commit theft that deprives the owner of the property. See id. 31.06(a)(1) (Vernon Supp. 2000). The State also may prove the accused's requisite intent by direct evidence. See id. 31.06(d) (Vernon Supp. 2000).