Defined number of parts that are assembled in a linear, step by step way to produce the outcome - a bicycle.

Clearly defined boundaries - design, manufacture/procurement of parts, and assembly.

Specific inputs - labour, parts, plant & equipment, energy, etc - resulting in predictable outcomes.

Arguably non-controversial, unless we are talking e-bikes (in which case the safety of other road users and pedestrians must be taken into account, as well as responsible disposal of batteries, etc), ethical supply chains, clean manufacturing, and other ethical issues.

Similar to the bicycle case, although the technical elements are richer (eg specialised labour for hand-made watches).

Potentially complex, when considering social, cultural, religious, labour, and geo-political issues in the country where it is being installed.

defined no. of parts

parts work together in step-by-step way

failure does not generally have dire consequence

might tend towards complex if it becomes part of a network of mixed road traffic or a component of large no. of bikes competing in a race, or travelling as a solo bike on a high pedestrian path