Kolam Tiles

Active now
Interactive
Combinatorics
Kolams
Binary kolam tiles on square boards and polyhedral surfaces: local matching, global connectivity, graph structure, symmetry, puzzles, and interactive constructions.
Author

Mohan Rajendran

Published

15 July 2026

Modified

20 July 2026

STATUS · ACTIVE NOW

The question

What global forms emerge when binary kolam tiles are assembled under local edge-matching rules?

Current focus
Connecting square-tile puzzles and triangular-tile polyhedra through graphs, symmetry, and interactive constructions.

Latest update
The octahedron explorer and its graph-theoretic article now join the three square-tile sandboxes.

Open the interactive laboratory

Why this project

The square branch begins with the sixteen four-bit words. Each word describes the openings of a square tile in the directions east, north, west and south. Adjacent bits must match, the outer boundary must close, and the fifteen nonzero tiles must form one connected network.

Setting aside the \(0000\) tile turns the same objects into a labelled 15-puzzle. The question changes from which boards are valid? to which valid boards can be joined by legal slides? This brings parity and orbit structure into the picture.

The triangular branch uses the eight three-bit words on the faces of an octahedron. Passing to the dual cube turns each tile label into a vertex degree. The degree sequence forces a seven-vertex tree, and its three possible arm-length patterns give a complete classification without exhaustive computation.

Project strands

Square tiles

Build a connected \(4\times4\) kolam, explore the associated labelled 15-puzzle, and compare configurations in the same sliding orbit.

Triangular tiles

Place eight oriented tiles on an octahedron, reveal the dual-cube tree, and fold each connected net into the completed solid.

Explain

Connect the experiments to binary encodings, graph connectivity, Euler characteristic, enumeration, and symmetry.

Articles

Interactive laboratory

  1. Square Kolam Tile Challenge — use every square tile exactly once.
  2. Slide to a New Kolam — explore the two sliding-puzzle orbits.
  3. Move X to Y — transform one valid square kolam into another.
  4. Kolams on an Octahedron — fold and rotate the three triangular representatives.

Classroom material

Next steps

  • give the two square sliding-puzzle routes permanent descriptive URLs while preserving the existing paths;
  • add downloadable triangular tile sheets and classroom material;
  • record a video walkthrough connecting the octahedron, dual cube, and subdivided \(Y\);
  • publish reproducibility material for the computational square-tile count.
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