Straight match, strip by strip
How a repeating pattern lines up when every drop starts on the same phase.
ReadGuides
Straight match, half drop, openings, units, and a full numeric example.
Half drop: the offset strip
Why alternate drops need an extra half repeat.
ReadOpenings, and what still comes off the roll
Moving a window changes the picture, not the number of strips.
ReadCentimetres, inches, metres, and feet
One plan, two ways to type the wall.
ReadHow many strips a roll width creates
Ceil of wall width divided by roll width, with a short last strip.
ReadWorked example: one wall, one window, straight match
Inputs, roll list, and assumptions in HTML.
ReadStart with the worked example if you want the inputs and the result without using the tool.