McKINNEY, Texas: IBM once was legendary for the large signs it hung in its offices reminding workers: THINK. But these days, thinking can be hazardous in some companies. Take Evan Brown, a former employee of DSC Communications. After the company found out that Brown had dreamed up a way to convert old computer code into an easier-to-use computer language, DSC demanded he turn over the idea, since he had signed an agreement which gives the company ownership of anything he develops while on staff. Brown, who says he developed the idea on his own time, won't budge, insisting that he never wrote the concept down. DSC fired him, but is now taking him to court to try to pry it loose. He's already turned down DSC's offer of $2 million for his thoughts. Maybe it would be cheaper if they'd just put up some of those big signs and see what develops.