Marbleslides: Rationals transforms the hyperbola from a static drawing on a whiteboard into a dynamic object. It turns the abstract notation of $y = \fracax-h + k$ into a toolkit for solving spatial puzzles.
It is notoriously difficult to explain why a graph has two separate branches. By treating the vertical asymptote as a physical barrier that the marbles cannot cross (and indeed, will slide away from), the concept of discontinuity becomes tangible. marbleslides rationals