thinglab

from The Free On-line Dictionary of Computing (8 July 2008)

ThingLab

   A {simulation} system written in {Smalltalk-80}.  It solves
   {constraints} using {value inference}.

   Version: ThingLab II.

   ["The Programming Language Aspects of ThingLab, A
   Constraint-Oriented Simulation Laboratory", A. Borning, ACM
   TOPLAS 3(4):353-387 (Oct 1981)].