Show sort indication on the scorecard

Hi,

I have a score card component and it is sorted (from behavior) on display by clicking on the header. But the user has a unique request.

User say he/she will come to know about the sorting only when they click, other wise they will not know. They need some indication that by clicking on the header, the score card could be sorted. I was planning of putting an arrow as an indicator but it will be static. User needs a dynamic arrow which goes up and down while clicking.

Any ideas highly appreciated.

Arun