e.g. in a this extract

vehicles
(vehicles by number of wheels)
- monocycles
- bicycles
- - motor bicycles
- - pedal bicycles
- tricycles
- four-wheeled vehicles
(vehicles by motive power)
- mechanically powered vehicles
- - motor bicycles
- - motor cars
- human powered vehicles
- - pedal bicycles
- hybrid human/mechanically powered vehicles
- - mopeds

the complete array of sibling terms under vehicles consists of

monocycles
bicycles
tricycles
four-wheeled vehicles
mechanically powered vehicles
human powered vehicles
hybrid human/mechanically powered vehicles

This may be subdivided into subsets by grouping under the node labels, forming two smaller arrays:

monocycles
bicycles
tricycles
four-wheeled vehicles

and

mechanically powered vehicles
human powered vehicles
hybrid human/mechanically powered vehicles.

Another array, at a lower level, under the broader term bicycles, is composed of the two sibling terms

motor bicycles
pedal bicycles

See the note under characteristic of division on the options for dealing with hybrids such as mopeds.