Advances in computer-generated effects, as well as the hardware and software used to create them, means it's now possible to visual complex concepts in real-time. Take Disney, which played around with several such ideas for the insides of Big Hero 6's portal, in particular this "mandelbulb".
A few days ago, Disney posted the following tweet showing off the effect.
The #BigHero6 effects team experimented with compositing fractals of varying shapes, sizes and colors when developing the "Into The Portal" sequence in the film. #TechTuesday pic.twitter.com/8dxDpGwAQu
— Disney Animation (@DisneyAnimation) May 1, 2018
A 3D fractal is actually called a "mandelbulb". As Wikipedia explains:
A canonical 3-dimensional Mandelbrot set does not exist, since there is no 3-dimensional analogue of the 2-dimensional space of complex numbers. It is possible to construct Mandelbrot sets in 4 dimensions using quaternions and bicomplex numbers.
If you feel like you've seen this effect more recently than BH6, it was also used in the film Annihilation.