A collection of the 22 most interesting and most shareable bookmarks of websites I discovered in 2025. They appear in no particular order and are organized into three categories. I have been able to collect and organize them thanks to the great piece of software that is Readeck.

Science and math

• Adventures in State Space (Video): A great visualization of the states and solutions to moving-block puzzles. You can see the structure of the state space reflecting the properties of the puzzles.

• Space Elevator (Interactive): An educational adventure from the ground up into space showing the relative heights of clouds, animals and different features of our atmosphere.

• A laser pointer at 2 billion fps makes the speed of light look... kinda weird (Video): The story of a tinkerer building an extremely fast camera and his fascinating results trying to capture the speed of light.

• Borazine - Molecule of the Month: An explanation of why borazine is special and sometimes referred to as "inorganic benzene".

• Entire Order and Chaos of the Double Pendulum Visualized (Video): A trippy attempt at visualizing the chaotic nature of double pendulums.

• 5D Diplomacy with Multiverse Time-Travel. (Video): A commendable attempt at applying the ideas of the silly "5D chess with multiverse time-travel" to the asymmetric board game of "Diplomacy" - with great visuals.

• D/A and A/D | Digital Show and Tell (Monty Montgomery @ xiph.org) (Video): An in-depth explanation of digital signal processing and how digital-to-analog converters do not produce blocky sound waves.

• Reservoir Sampling: An explanation of an interesting algorithm to create fair samples with good visualizations and interactive elements.

Programming and software

• jank programming language: An experimental LISP dialect inspired by Clojure but integrating with the LLVM compiler toolchain and thus able to directly call C++ code from LISP.

• A calculator app? Anyone could make that.: An in-depth explanation about how the default calculator app on Android actually uses a sophisticated, yet elegant algebraic number model allowing to calculate surprisingly many expressions exactly instead of using floating point approximations. The app was written by the famous Hans-J. Boehm.

• Ten years in the future: Hacker News: A purposefully funny prediction of the future headlines of technology discussions - generated by an LLM. See also the discussion on Hacker News where somebody also posted an interactive version.

• Australia/Lord_Howe is the weirdest timezone: An explanation of the weird rules that govern time zones and how they can (and cannot) be modeled by computers.

• Full Haskell-like Type Class resolution in Java: An experiment in implementing the semantics of type classes in Java with existing language features.

• SVGs that feel like GIFs: Animated vector graphics on the web are possible and apparently supported by browsers.

• The UX of HTML - HTMHell: An analysis of how modern websites often neglect subtle but vital aspects of usability with their complex implementations. Aspects which you get for free with simple HTML. Also, this website has a great name.

Great curiosities

• Models of European Metro Stations: A collection of isometric visualizations and analysis of the subterranean layouts of many European subway stations.

• Aspidochelone (Wikipedia): The name of a giant fabled sea beast so large that sailors mistake as an island. This article is a unifying link between the recurring iterations of this common theme in myths and literature.

• Land of Punt (Wikipedia): An ancient kingdom we know for sure existed, but we have no idea where.

• How Many Days Since The Montague Street Bridge Has Been Hit? A quirky site where the author tracks how often trucks and buses collide with a particular local bridge with low clearance. Apparently quite often. ¹

• Riding high in Germany on the world’s oldest suspended railway: A British article about the German Schwebebahn. It's intriguing to have an outsider's view of this.

• Tokyo's Map, Explained (Video): An interesting exploration of how the layout of Tokyo reflects its history.

• Pompeii: Spectacular new discoveries unearthed include private spa: Interesting new findings in Pompeii.