Grid Recursion

A navigation technique where a grid cell can be further subdivided into a finer sub-grid, allowing users to achieve progressively more precise positioning through successive levels of refinement. For example, a 3x3 top-level grid provides 9 positions; descending one level into a cell creates a 9x9 effective grid (81 positions), and a third level yields a 27x27 grid (729 positions). Grid recursion enables non-visual users to locate specific points in a two-dimensional space using only a small set of keys, making it practical to interact with graphics, maps, and spatial content through keyboard-only or switch-based input without requiring a pointing device.