##Puzzles

The Wending House: a Myst-like library and memory palace that holds all of these devices, plus drafts, books, and puzzles. Doors keep hours, mirrors hide rooms, the sky and weather are real, and some loops take you somewhere else. A curator’s guide explains how it’s built.

  • Defectsweeper: find the dislocations hidden in a hexagonal crystal by walking Burgers circuits.

  • Fifteen and the Parity Dial: the 15 puzzle with its permutation, parity invariant, and commutators shown live. Of Instruments: the cabinet of instrument folios, each drawn as plates in a manuscript, in ink on vellum, with exercises that tick themselves.

  • The Sector: Galileo’s compass of proportion: the lines of lines, planes, and solids, the dividers, and the proportional compass.
  • Napier’s Bones: the bones, the Genaille–Lucas rulers that do their own carrying, and Napier’s binary chessboard.
  • The Slide Rule: a plain Mannheim rule with its scales, and Gunter’s line with a pair of dividers.
  • The Vernier: read a tenth of a division by coincidence, on a caliper, the arc of a sextant, and a micrometer screw.
  • Slide Rule Cabinet: straight, circular, complex, finite-field, and relativistic slide rules to drag and read.
  • Stereonet Slide Rule: the SO(3) slide rule, a Wulff net with a turning overlay and a frame-matching challenge.
  • Hamilton’s Turns: compose rotations by laying arcs head to tail on a sphere.
  • The Rule of Turns: a slide rule for SO(3), drawn as an engraved globe: Hamilton’s turns slid together, the self-generating scale, the commutator, and the belt.
  • Cross-Ratio Ruler: read true distances off a picture, on a road, a tiled floor, and by the harmonic construction (first edition).
  • Tropical Slide Rule: watch addition turn into max as the base of a log scale grows.
  • Quaternion Cards: a card game in the quaternion group, where left and right differ.
  • p-adic Ruler: a branching-tree ruler for p-adic distance.
  • Galois Lock: a lock whose moves are the Galois group of x⁴ − 2.
  • Planimeter Bench: measure area by tracing with five drawn instruments (polar, linear, hatchet, radial, and a counting frame) and a running error budget (first edition).
  • Fraction Target: make the target from four fraction cards, with every deal solvable (MATH 102 practice).
  • Lily Pads: sticky growth in a pond, where pads grow until they jam and let go only when a contact is pulled apart.

The Garden: twelve raised beds to look after, tamagotchi style. They keep growing in your browser while you’re away: water them, pull weeds, pick off snails, and harvest what ripens before it wilts.