The knex drive chain is composed of interlocking links which can be connected and disconnected from one another to make a drive chain of arbitrary length. Each chain link can have a connector attatched to it.
The picture below shows that nine links of chain are needed to span the length of a gray strut.
The picture below shows that to make a 180 degree loop around a drive chain wheel composed of two red gears, slightly less than four links are needed.
