This visualizer shows how fulcrum points affect character rotation. This is done by rendering forces applied to fulcrum points and reverse forces applied to character's center of mass.
If these forces are aligned with the line that connects a fulcrum point and the center of mass, there is no rotation (left side of the image).
If they are not on this line, it means the character is rotating (right side of the image).
Each of the fulcrum points is a momentary point calculated individually for every frame.
A fulcrum point should be located within a fulcrum area (the part of the character on the ground level). Otherwise, the motion won't be physically accurate.