Four directions — Cartonnage

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Paper height

Margin Seed Cell Lines per cell

12×12 mat — 8.50″ × 11.00″ — 80 strokes, 4 pens

LeWitt's four directions — a grid of cells each hatched flat, upright, or on one of the two diagonals — drawn once in a quadrant and mirrored out, so a reflection sends θ to 180−θ and two reflections put it back. Each run of neighbouring cells sharing a direction is hatched as one serpentine: the pen turns at the end of every line by walking the run's own border to the next, which costs a pen-down per region instead of one per line and hides every turn under the grid, which is drawn. Every direction hatches on the grid's lattice rather than each region's, so a region that spans cells is still ruled by the grid it sits in. The count is a flat or upright hatching's — one line halves the cell, and a diagonal takes the lattice's own 45° lines, closer together by √2, so it cuts the cell in four.