Interactive projects

Things I built to understand, or to explain: simulations you can run, change and break, each with a short write-up of the physics or mathematics behind it.

16 projects

  • Physics simulations

    Three-Body Problem

    Figure-eight, butterfly and other periodic orbits of three gravitating bodies, integrated live, plus a free mode to throw your own.

    • Celestial mechanics
    • Chaos
    • Numerical integration
  • Physics simulations

    Chaos in a Magnetic Pendulum

    A pendulum over three magnets: sensitive dependence on initial conditions, Lyapunov exponents and basins of attraction.

    • Chaos
    • Lyapunov exponent
    • RK4
  • Physics simulations

    Light Curves of Binary Stars

    Two stars on Keplerian orbits and the light curve a telescope would record, eclipses included.

    • Astrophysics
    • Kepler orbits
    • Photometry
  • Physics simulations

    Planetary Connecting Lines

    Draw the line between two planets every few days and a flower appears: the geometry of Earth, Venus and Mars.

    • Orbits
    • Geometry
    • Generative
  • Physics simulations

    Particle Physics Playground

    Charged particles under Coulomb forces, gravity and a magnetic field. Launch your own with a drag.

    • Electromagnetism
    • N-body
    • Sandbox
  • Mathematics

    Seeing the 3-Sphere

    Quaternions, the Hopf fibration and stereographic projection: what a four-dimensional sphere looks like from inside our space.

    • Topology
    • Quaternions
    • Hopf fibration
  • Mathematics

    The Arrowed Rubik's Cube

    Arrows on the centres of a Rubik’s cube: why one centre can never be turned on its own, and why (UR)¹⁰⁵ brings the stickers home but not the arrows.

    • Group theory
    • Permutations
  • Mathematics

    The Picture-Hanging Puzzle

    Hang a picture on n nails so that pulling out any one makes it fall: free groups and commutators at work.

    • Free groups
    • Topology
    • Puzzles
  • Mathematics

    Buffon's Needle

    Estimate π by dropping needles on a striped floor, and watch the Monte Carlo estimate and its error bar converge.

    • Monte Carlo
    • Probability
  • Machine learning

    Physics-Informed vs Raw Neural Network

    Two classifiers learn projectile motion side by side: one is given the physics, one has to discover it.

    • Neural networks
    • Physics-informed ML
  • Life & perception

    Spatial Epidemic (SIRD) Model

    Agents wander, meet and infect each other, then recover or die: an agent-based SIRD model with Monte Carlo statistics.

    • Epidemiology
    • Agent-based models
    • Monte Carlo
  • Life & perception

    Purple at Fixation

    Purple looks purple where you look and blue everywhere else: a colour illusion from vision research, with a reader vote.

    • Perception
    • Colour vision
  • Research

    Phase Diagram of Quark Matter

    A map of the phases of strongly interacting matter, from hadrons to color superconductors, as used in my research.

    • QCD
    • Color superconductivity
  • Research

    TOV Extravaganza

    My open-source Python toolkit for neutron-star structure: masses, radii and tidal deformabilities from an equation of state.

    • Neutron stars
    • Python
    • Open source
  • Just for fun

    The Magic Tube

    A tribute to ELIZA, the 1960s chatbot: a retro terminal oracle with opinions on physics, Persian food and everything else.

    • Chatbot
    • Retro
  • Just for fun

    Polygon Bouncer

    Balls bouncing inside a polygon: a small, satisfying collision sandbox.

    • Collisions
    • Generative