The Logrus-Foils, shapeshifting weapons of tremendous power, Chaosian counterparts to the Patternblades, quite possibly containing an extension of the Logrus. Like the Patternblades, they cut nearly anything and slice through magics like they weren't there. However, the blades ignite the blood of anybody with Amberite blood within them if they are nicked. They are also capable of shapeshifting into a nearly infinite number of forms, the most common being some form of blade and a whip.
There are no such things as 'Logrusfoils' in the Zelazny canon, as they are merely a GM invention to counterbalance the existance of the Patternblades.
It does seem logical that they'd exist, even if they're not really canon. The secrets of making them might be lost, the owners secretive, and so forth. A good way to pull a surprise on your players. --KeepRats/DaR