An infinitive is the base form of a verb, usually preceded by to. It can function as a noun (subject, object, complement), adjective, or adverb. In diagrams, it sits on a pedestal — a diagonal to line plus a horizontal that holds the verb.
The Infinitive Pedestal
“To own her own car has long been her desire.”
Step 77 — infinitive phrase 'to own her own car' as subject
The infinitive phrase to own her own car is the subject. The stem rises from the subject position on the baseline to a horizontal platform carrying the verb own.
Infinitive as Direct Object
“Bob hates to wash dishes and take out the garbage.”
Step 78 — compound infinitive phrase as direct object