Arrow Circle & Arrow symbol on chart

[#1]

From my attached screen shot, i would like to know what are those symbol's are in black circles. I got this screen shot from one of the demo application. 

Thanks.

[CELAMBARASAN]

Hi,

     Arrow Symbol is a Drill down group of dimension.

     Arrow Circle is a Cyclic group of dimensions.

     Drill down group --> Hierarchy structure like Year-->(has 4)Quarter-->(has 3)Month-->(has 4)Week-->(has 7)Day

     Cyclic Group --> Its just changing the dimension as our need in single chart.

Celambarasan