Drawing conics on a hexagonal grid
M. L. V. Pitteway · Proceedings Fifth International Conference on Information Visualisation · 2002
An algorithm is presented which can be used to outline ellipses, circles, or any of the other conic sections on a hexagonal lattice. The basic algorithm requires just one test and three add operations in the inner loop, though an additional test is required to detect a change in the overall direction between two adjacent sectants.