100 million ball mushroom billiard is (not) chaotic @animations

Uploaded May 2026 | Updated September 2026, 2 weeks ago

The Bunimovich mushroom billiard is chaotic for some initial conditions and integrable/non-chaotic for some other, which is perhaps not too surprising considering the geometry of the domain.

1. Starting in the foot is always chaotic, regardless of the initial velocities.
2. Starting high in the hat is typically non-chaotic depending on the initial velocities. Here is shown a non-chaotic time evolution.
3. Here the initial conditions are such that half of the point distribution exhibits chaos (orange/yellow) whereas the cyan part is non-chaotic.

Music by @gpcbass . The song is called Alhambra and used on this channel before.

Visuals in Python and FFmpeg. Matplotlib was used in 1. and 2., whereas PIL was used in 3.

100 million ball mushroom billiard is (not) chaotic

$Raytraced 2D diamonds Ordinary and heart-shaped two-dimensional diamonds (refractive index ~2.4) are exposed to a thin beam of white light consisting of 250 000 wavelengths. GPU throughout. Approx 1.5 hours rendering time per minute of video. Song by @gpcbass, called Twelve Grapes. Visuals in Python & FFmpeg$

134217728 balls falling on a right-angled wedge

Balls dropped on a cone, f(x, y) = sqrt(x^2 + y^2)

Just another Fourier expanded step function

$Photographing a trillion-star galaxy (quick-and-dirty how-to) Shown is an image I took earlier this year of one of the most majestic galaxies as seen from us; the M101 (so-called Pinwheel galaxy). Its located about 20 million lightyears from us and houses approx 1 trillion stars. Its face-on characteristic is a truly spectacular sight. Image acquisition was done with ZWOs AM5 mount and ASI2600MC PRO camera through a Skywatcher 100ED DS-PRO refractor with a .85 reducer, i.e., at 765 mm focal length and f/7.65. Taken from a Bortle 4 zone. In total 80 5-minute exposures (6 hours and 20 minutes). Stacking, edge cropping and background extraction was made in Siril, and the remaining postprocessing in PixInsight. Particularly, the magic wands Blur- and Noise exterminator were used therein. I spend typically 30 minutes on post and have much to learn as some may notice. No affiliation involved. Astrophoto channels I like: @NebulaPhotos Nico is brilliant on what he does and is the main reason that I eventually went into astrophoto two years ago (with a DSLR and a tripod). @lukomatico Superb in-depth comparisons among gears, and always provide interesting tutorials and reviews. @CuivTheLazyGeek Enthusiastic and entertaining reviews/comparisons/tutorials. Always a pleasure to watch. Visuals made with my astro camera and telescope; images stitched and blended in ffmpeg, as well as some Python tweaks. The beautiful music was made by @gpcbass; the song title is Starless (a King Crimson cover from 2022). A vocal version can be found here: https://www.youtube.com/watch?v=TbJvKYycOAY&ab_channel=gpcbass$

Spiral of 999 balls with varying bounciness dropped on parabola

Gaussian wavepacket bouncing in a 2D box