Ok on request here is how you achieve a half tone effect here only i used the shape of a circle . if you want it around a specific shape you must copy the outline of that shape and repeat the same then increase the size of the same shape , with reversal of colors you can get different effect
enjoy! lemme know if it was helpful

If you would like to edit it change colour or increse in size here is how you will expand it!

Right click the circle and ungroup
slect the colour you would like to change to

go to select > same > fill colour
and change to whatever which ever colour you will like!

discuss this topic to forum