A legendary feature of Infocom's ZMachine Virtual Architecture for Interactive Fiction. The Tandy bit, when set (eg, on games running on Tandy computers or published through Tandy) would have strange effects: In Deadline it caused private dicks to be replaced with private eyes (among other things) and it suppressed Zork I from indicating that it had sequels. Although popular myth has it that this 'feature' was included at Tandy's lawyers' behest, it seems more likely that it was just someone at Infocom showing off. After all, any suitably arcane magick is indistinguishable from technology.