Graphical representation of length "b" from hyperbola equation

It would be great if, within the unit on hyperbolae and their foci (Conic sections), we could SEE what length "b" from the equations x^2/a^2 - y^2/b^2 is on the graph. Length "a" is clearly shown as the distance from the vertex to the center, but length "b" is not graphically represented.