On the dashboard of our family car is a shallow indentation...

On the dashboard of our family car is a shallow indentation about the size of a paperback book. If you are looking for somewhere to put your sunglasses or spare change, it is the obvious place, and it works extremely well, I must say, so long as the car is not actually moving. However, as soon as you put the car in motion ... everything slides off ... It can hold nothing that has not been nailed to it. So I ask you: what then is it for?