Hanisch, Frank-2015-12-102015-12-106-8-2004-http://dx.doi.org/10.2312/cgems04-11-1369This interactive CGEM illustrates the marching squares algorithm, a 2D isoline representation technique commonly used for contouring. Teachers may also use this CGEM to introduce the 3D marching cubes algorithm, which uses the same approach [1]. Users can directly manipulate two circle objects. The shape of the objects is considered unknown. After sampling the objects on a regular grid, the marching squares algorithm approximates the contour. Users may move the circles to adjacent locations to experience how we resolve ambiguous cases by an additional midpoint test.Curves and surfacesScientific visualizationAlgorithmicApplication DomainsModeling TechniquesSoftwareTechnology10.2312/cgems04-11-1369Frank Hanisch-Curves and surfaces, Scientific visualization, Algorithmic, Application Domains, Modeling Techniques, Software, Technology