componer

to compose (write music)irregular-er verb

Where it breaks the pattern

componer follows poner: irregular first-person form
componer follows poner: irregular preterite stem; the 1s and 3s endings are unstressed, so they carry no written accent
componer follows poner: irregular future stem; the endings themselves are regular
componer follows poner: conditional shares the irregular future stem
componer follows poner: present subjunctive is built from the irregular yo form
componer follows poner: imperfect subjunctive is built from the third-person preterite stem
irregular past participle

Indicativo: componer conjugation

	Presente	Pretérito	Imperfecto	Futuro	Condicional
yo	compongo	compuse	componía	compondré	compondría
tú	compones	compusiste	componías	compondrás	compondrías
él / ella / Ud.	compone	compuso	componía	compondrá	compondría
nosotros	componemos	compusimos	componíamos	compondremos	compondríamos
vosotros	componéis	compusisteis	componíais	compondréis	compondríais
ellos / Uds.	componen	compusieron	componían	compondrán	compondrían

Participio: compuesto · Gerundio: componiendo

irregular form

Real sentences with the conjugated form highlighted, from Tatoeba, licensed under CC BY 2.0 FR.

Ese grupo se compone de seis miembros.
The group is made up of six members.
Me las compondré de algún modo.
I'll get along somehow.
El prodigio de cuatro años compuso una sinfonía.
The four-year old prodigy composed a symphony.

These verbs are poner with a prefix, and they inherit its irregular forms.