A mathematical paper by S. A. Shorter on the sateen (satin) arrangement of points on squared paper, used both for weave construction and for distributing ornamental repeats. It restates the two classical rules (order and step prime to each other; complementary steps give mirror images) and adds a third rule from rotation by a right angle to count distinct sateens of a given order. It then develops the 'sateen lattice', gives formulas for order and step from lattice measurements, and discusses 'twilliness' and 'perfect' sateens, with a table of the first seven. Diagrams of sateen grids illustrate the argument.