Problems from work and play, made playable
Finance
Monte Carlo Without a Covariance Matrix
Correlated stock returns, drawn one normal per day of history instead of one per asset
A Flat Distribution of Defaults
A credit basket where every number of defaults — none, one, all of them — is equally likely
Quantiles
The tallest person in the room is not the tallest person — with n data, the largest never sits at 100% and the smallest never sits at 0%
Operations Research
Where to Look First
Not the travelling salesman's route — you stop when you find it, so the legs at the end may never be driven
When the Map Is Only a Table
The same search on a graph, where the costs need not be distances and the places need not be equally likely
The Ball That Rolls Downhill
Solving a linear program from the inside, by growing the largest ball that fits and sliding it downhill
Recreational Math
Spectre Monotile
Explore the aperiodic monotile discovered in 2023
Barnsley Fern
Fractal fern using iterated function systems
Multiplication on a Circle
Cardioid patterns from modular multiplication
Spiral Circles
Tangent circles in spiral arrangements
FLW Circles
Nested rings inspired by Frank Lloyd Wright
Bresenham Line Algorithm
Line drawing on a pixel grid
Izzy Triangles
Colorings of a triangle cut into six, counted up to rotation
Rotating Links
Linked segments with configurable rotation
Cherry Arbor Design
Puzzles
Craft
Ammann-Beenker Tiling
Aperiodic tiling with squares and rhombi
Celtic Knots
Creating intricate Celtic knot patterns
Cipra City
Line tiles forming continuous roads
Cipra Loops
Tiles with path connections on edges
Corona Tiles
Exploring Heesch numbers and tessellation
Ferns
Barnsley fern crafts and theater sets
Nessie
Parallelogram-based tiles with fluid shapes
Archimedes' Puzzling Dissection
Archimedes' ancient dissection puzzle
Lexen's Tricurve
Tim Lexen's curved-edge tile