Well, you just don't get a serious (and detectable) "wave" without at least two mightily density things doing a complex dance with mightily high acceleration. So it's good to have a few million-solar-masses black holes merging or in near orbit.

See This Wikipedia Entry:

*A more dramatic example of radiated gravitational energy is represented by two solar mass neutron stars orbiting at a distance from each other of 1.89×108 m (only 0.63 light-seconds apart). [The Sun is 8 light minutes from the Earth.] Plugging their masses into the above equation shows that the gravitational radiation from them would be 1.38×1028 watts, which is about 100 times more than the Sun's electromagnetic radiation.*

Mathematically, this is hairy because the solutions to the equations are nonlinear (adding two solutions does not yield a solution), so numerical approximations are needed.

It is also evidently not easy to depict. The first part of the video doesn't show a black hole; it shows a black ball. In the second part, the third space dimension seems to have been dropped so these should be "circles" (but what is the "time" of that plane? This is not a Newtonian space that allows constant-time planes).