Bicycle wheel the number of spokes that any one spoke crosses. Conventionally laced 36- or 32-spoke wheels are most commonly built as a cross-3 or a cross-2, however other cross-numbers are also possible. The angle at which the spoke interfaces the hub is not solely determined by the cross-number; as spoke count and hub diameter will lead to significantly different spoke angles. For all common tension-spoke wheels with crossed spokes, a torque applied to the hub will result in one half of the spokes - called "leading spokes" tensioned to drive the rim, while other half - "trailing spokes" are tensioned only
Counting rods Counting rods Counting rods () are small bars, typically 3–14 cm long, that were used by mathematicians for calculation in ancient East Asia. They are placed either horizontally or vertically to represent any integer or rational number. The written forms based on them are called rod numerals. They are a true positional numeral system with digits for 1–9 and a blank for 0, from the Warring states period (circa 475 BCE) to the 16th century. Chinese arithmeticians used counting rods well over two thousand years ago. In 1954 forty-odd counting rods of the Warring States period (5th century BCE to