ultra-short, illustrative story for patterns

Story provides a more narrative, less academic description to a pattern. When a pattern has a good narrative description at the first few sections, it helps people deciding quickly whether this is something they want to dive deeper. Some patterns provide good narrative while some other patterns lack those narrative angle. It would help to add story or improve narrative description to the patterns that don't have good narratives.

En el issue no se mencionan archivos ni pruebas. Revisa los documentos de patterns del repositorio e identifica las entradas cuyas secciones iniciales carecen de una narrativa concisa; se considera terminado cuando los patterns seleccionados tienen historias útiles que ayudan a los lectores a decidir si quieren seguir explorando.