Visualization is gaining in popularity as a means of monitoring and debugging logic programs. A well-drawn picture can quickly reveal information that would take a significant amount of time and effort to uncover from text-based representations. The goal of the Wand research project at the University of Saskatchewan is to provide a set of graphical debugging tools which are language independent, easily tailorable, and useful for monitoring and debugging logic programming computations. ICOLA (Incremental Constraint-based Object Layout Algorithm) is a graphics engine for the Wand system. ICOLA positions graphical objects according to object declarations and constraints specifying the relative positions of the objects. ICOLA is capable of drawing pictures from highly under-constrained constraint-based picture descriptions without requiring the specification of absolute object positions. This thesis presents new capabilities of ICOLA designed and implemented as M.Sc. research work. All l...