Torus-shaped links are used in chains that are intended for lifting,
tugging, or securing (such as when used with a bicycle lock). These chains
are flexible in two dimensions, with the chain's length acting as a fixed
third dimension. An example of these types that is primarily decorative are
little chains used as jewellery.
Those made to transfer power in machines have links made to fit the
machine's sprockets' teeth and are only one-dimensionally flexible. Although
there are non-roller chains like block chains, they are referred to be