the mail boxes in order to be noticed have to be red (even though in spain and france they think yellow is brighter, and in the usa on some absurd grounds they paint them blue), the mail boxes stand out in the urban landscape in the same way flowers do in the rural setting. they have to do so in order to fulfil their social function: as flowers attract insects, which in their way pollinate others, the mail boxes attract love letters and small parcels which mailmen take to some precise but remote destinations.

b is for buzón

buzón: 1.letterbox; mailbox 2.postbox; letterbox; mailbox 3.to post or mail a letter