Is it correct that this Bokeh image is not only caused by out-of-focus but also the shape of aperture?

How could we model moving bokeh in an animated scene to simulate a change in focus?

@tsk YES the shape of the bokeh is indeed reflective of the shape of the aperture! In fact you can DIY heart shaped bokeh!

Bokeh originated from the Japanese word ぼけ, which can mean "blur", among the various meanings that it has. Wikipedia has a nice article about how this word got adopted as a photography jargon: https://en.wikipedia.org/wiki/Bokeh.