If the earth is flat .. exactly where is ZERO???
same dilema as moving from 3D to Robotics .. just another percpective! When working in an artificial sandboxed environment there is UP and DOWN gravity which lies separated from the center ZERO of dimension XYZ....... In Robotics ZERO dimension is always the center of the robot itself. IN REAL TIME we work in REAL 3D which makes the center of gravity and the centerof dimension the same point ZERO .. all else works out from there, therefore the flat surface is the points at a distanced from zero in all dimensions.
making it a logical sphere .. unless your in 2D or something! ~Aliceincode