This 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.
