This part deals with the past wishful thinking of someone about how good/happy it would have been to possess /have something in the past though actually they didn’t possess it.
- He wished he had had a pet dog when he was a boy..(i.e He wished so but he didn’t have it)
- She wished she had had a post graduation in Science.(i.e she wished so but didn’t have..)
- She wished she had had long hair.
- The Head Mistress wished the school had had a beautiful garden.
- John wished he had had a motor bike.
- The poor man wished he had had a house of his own.
Note: In all the above cases the subject of the sentence wished to possess something which actually they didn’t possess. The past perfect form of ‘ Had’ is ‘Had Had” and therefore in order to show an unfulfilled wish or desire ,we have to use ‘ HAD HAD’ and Not ‘HAD’.