Every Widener wussie knows the red line on the floor leads deep down to Pusey and the yellow stripe lights the way to Lamont. But now, without warning: a third line. Blue. The cocky and new-looking line begs two questions--why and where does it go? Barbara A. Mitchell, head of Access Services in Widener Library, spilled the beans on new blue: It's only temporary. The on-going Widener construction has blocked an exit and the blue line will take after-hours bookworms out of the library via the backroads--through the Staff Lounge (which Mitchell reminds are "not open to patrons"), past the photocopying area and out the West Exit into the Yard. Bon voyage.