Tesseract Gauntlet

Six constraint families — hover to trace one on the board

Amber cells share a classic group with your selection; teal cells share a four-dimensional one.

The same 81 cells at their true positions in the lattice. Drag to turn it in 3-space; shift-drag (or 4D drag) to turn it through w and watch it fold inside out. Click any digit to select it — its six constraint planes render in place.

select a cell 0 / 81

How this is four-dimensional

Every cell lives at coordinates (x, y, z, w), each running 0–2. x, y place you inside a block; z, w place the block in the meta-grid. So the board is a 3×3×3×3 hypercube unfolded onto your screen.

Pick any two coordinates to freeze and let the other two vary: that 9-cell plane must contain each digit exactly once. Four coordinates give 6 ways to choose the pair, and 9 planes each — 54 groups, versus ordinary sudoku’s 27:

Row, Column, Block — the familiar three.
Pillar — the same row of each block, down one block-column.
Band — the same column of each block, across one block-row.
Echo — the same square in all nine blocks.

The extra constraints are also extra tools: a digit placed anywhere rules it out of four planes at once. Use the teal highlights.

Trainer — the cursor jumps to a cell whose digit is already forced, and the answer slowly fades in. Call it before the ghost appears for full credit; wrong keys buzz and cost 25. Every correct entry spins the lattice by twice your completion percentage in degrees, so lock-ins hit harder as the hypercube fills.

Gauntlet — the trainer with teeth. The reveal window shrinks as the puzzle fills in, down to a quarter of its opening size by the last cell. Once a digit is fully visible it turns red and drains your score 5 points a second until you press it. And wrong keys scramble the board’s orientation — a rotation or mirror is a symmetry of the 4D constraints, so the puzzle is untouched; only your bearings are.

←↑↓→ move 1–9 place N notes Z undo H hint ⌫ erase

Hypersolved