A tractal device provides a tractile or tractive shearing force. A tractal device pulls, pushes and/or shapes things by supplying motive shearing forces (usually back and forth) to make them more appealing and/or useful.
Leather working tools provide the tractal action to shape a leather product and make it soft to the touch. Hands and fingers can provide tractal smoothing forces to moist pottery clay - turning it into something beautiful and useful.
by Mirths April 23, 2010