Now, for the question of which country borders Spain other than Andorra, France and Portugal - I accept that Morocco is a valid answer as I've crossed the borders between Morocco and both the Spanish enclaves of Ceuta and Melilla. However, I've also crossed the border from the UK enclave of Gibraltar into mainland Spain, so UK should also be an acceptable answer. Quod est demonstrandum.
I'm sure de Beers would disagree.