Bus terminals can be placed on wires, similar to regular terminals. When placed on a horizontal or vertical wire segment or on a wire vertex, a connection will be established automatically. The wire becomes a ``bus wire'' (though it looks visually like an ordinary wire).
A bus wire can tie together bus terminals and bus subcircuit connections.
Note that a bus wire can also serve as an ordinary wire, if it is additionally connected to scalar terminals and/or connection locations. However, this is not advised, as it can be very confusing.
Bus wires simply associate a collection of bus terminals and bus subcuit connectors that will be mutually connected. When actual connections are established, when iterating over the contacts, out of range indices are simply ignored.
For example, suppose the collection contains a terminal with width 6 and a subcircuit connector of width 4. The first four contacts of the bus terminal will be connected to the subcircuit, the remaining two terminals (the largest indices) will remain open.