What: Adhering to the rules of Islamic ornament or Sadu: the grid, the closing repeat, star symmetry.
Why: A pattern is a geometric system, not random drawing; fidelity to its rules preserves its spirit and beauty.
How: Build the grid with compass and ruler, ensure the repeat closes and the star is symmetric before executing.
Common mistake: Imitating the pattern's look with wrong proportions and angles, so its symmetry breaks.
Exercise: Execute an eight-point star on a geometric grid, and verify its points are equal and its pattern closes.