Robert Siegel talks to Chris Heschong about the Covers Project. It's a Web site devoted to finding strings of "cover" versions of popular songs. A "cover" version is simply a song redone by an artist other than the original artist. And a string means Artist "A" covered a song by Artist "B," who in turn covered a song by Artist "C," who covered a song by Artist "D," and so on. In the spirit of the "six degrees of separation," Heschong has created a list stringing more than 80 tunes together linked in this fashion.