I like puzzles, math, and algorithms. For eleven years, most of mine have been 110 inches wide.

The US containerboard business as a minimum-cost network flow, built from free public data: 63 mills from the 10-Ks, 441 box markets from the Census and the EPA registry, freight from distance and diesel, and the dual prices that say what a ton of capacity is worth, who would switch supplier for how much, which outage hurts most and when to take maintenance. Page by page, source by source, with the code, an animated solver, and a chat that shows its lookups. Open the app →

Gilbert's finite permutation groups doing work: the order of a riffle shuffle, Burnside counting the box designs that are really different (24 under rotation, 21 if you may flip), and Verhoeff's check digit, which uses the dihedral group D₅ to catch every transposition that mod-10 schemes miss. Every claim brute-forced.

Papadimitriou & Steiglitz ch. 14 on one picture. The LP says 7.57 truckloads; rounding breaks a constraint. Two Gomory cuts, each read straight off the simplex tableau and drawn in the plane, land on the integer optimum. Exact-fraction Python, checked against brute force on 290 instances.

Korte & Vygen §16.1 on a map of 69 US metros: greedy says 20 plants, the optimum is 18, Chvátal's bound promised 54. The instance that makes greedy look bad, the LP that proved the optimum for free, and the five plants that building a network one acquisition at a time costs you.

Korte & Vygen §11.1 in a box plant: the morning's orders-to-machines question solved as a min-cost flow by successive shortest paths. Step through the augmenting paths that re-route work greedy would strand, then read the dual prices that certify 686 minutes. Python engine checked against brute force.

Narrative to numbers, Damodaran-style: capacity out, price in, assets that are expensive to run — a DCF, a sum of the parts, and a Monte Carlo that turns the stock into one question about the containerboard cycle. Model and code included.

From an Excel Solver to a solver of my own: the floor, the mill, the math as I understand it now, and what I'd tell a data engineer who wants in. With a live search-space explorer and a real branch-and-bound trace.

A live performance dashboard for two 110" corrugators running 7 MMSF a day each — trim, shear, dry-end, speed with and without stops, downtime Pareto — and why a report of numbers finds nothing until someone converts the gaps to dollars.

Dijkstra, Bellman-Ford, and Floyd-Warshall on the same nine nodes — including the negative backhaul edge that makes Dijkstra confidently wrong, and the all-pairs matrix filling in.

Topological sort as the scheduler, critical path as the wall-clock bound, DFS cycle detection as the guardrail — and Kruskal's MST for the graph-theory nod. All animated.

LP, MILP, and CP-SAT — when each fits and when none does. A product-mix LP with shadow prices, and an OR-Tools job shop scheduled to proven optimality, with the Gantt.

Corrugated units, forklift-loaded through the rear door, stacked under footprint, roof, and weight rules — in 3D, with a heuristic that plans the stacks before anything moves.

Naive recursion → memoization → bottom-up → the cut plan, animated — then real cutting stock with trim loss and why column generation was invented at a paper company.

Greedy, DP, backtracking, and branch and bound on one instance, animated in d3 — then the same idea loading a 53-foot trailer. Java at the bottom.

An autograd engine built from scratch with every gradient checked by hand, then notes on each video in Karpathy's Zero to Hero series.

Bounded tools, application-owned numbers, evidence over narrative: how the corrugator shift investigator is built and what it refuses to claim.

One-to-one, onto, and the affine map f(x) = ax + b mod 26 — with and without the key, and where the same math shows up in production code.

PowerShell pipes objects, not text — why that's an advantage for AI coding agents, plus the full cmdlet reference.

Why the Unix philosophy turned out to be the ideal interface for machines that think in language, plus the full shell reference.