When using an offset design match, also called drop match, the design expands beyond the width of one roll and therefore needs to match the strips around it both horizontally and vertically. Offset designs are the most difficult to align and require you to determine which strips will go where before you begin. The half-drop match repeats at the ceiling line on every other strip creating a diagonal pattern sequence. Offset matches also require more wallpaper and create more waste. You would need three strips of wallpaper to repeat the vertical design.
The symbol for an offset match is .