The Wall conjures up images of a frustratingly impenetrable obstacle, but Dravid was much more than that.

BBC: The greatness of Rahul Dravid

And yet, there is a near impenetrable belief among anti-gun activists that guns are the cause of violence and crime.

CNN: The case for gun rights is stronger than you think

Certainly Brahms led his personal life in just such a fashion, presenting a gruff, impenetrable exterior to his friends, and never letting romantic attractions lead to commitment or even, so it seems, consummation.

ECONOMIST: How Brahms saved music from Wagner