How do I create a ring?

hii everyone , i want to create a ring which radius is grow from 0 to certain variable pixel let 30 pixel

i try to create with particle but particle is not what i want. i want to have a circle having a growing radius .

thanks for help

dropbox.com/s/cdrpv87sm64akpr/canvasexample.c3p

Example using the drawing canvas plugin to draw the circle, and a timer to control the rate it grows.

thanks oosyrag