JAVA worksheet: arrow, grid, invariant line
Use the RESET button (top-right) to go back to START.
Use the RUN/PAUSE button (bottom-left) to RUN the animation.
When the animation has finished,
RESET, then DRAG point A to a new position, RUN the animation again;
OR: don't RESET but DRAG point A to change the direction of the invariant line.
Created with GeoGebra