Showing only portions of circular sequences
I have constructed a page where I have a sequence of circles emerging from a point. The basic formula looks like this:
Sequence[Circle[S1, 2λ (t - i)], i, 0, 10]
Where 2*lambda is the distance between the circles, and t is the time parameter used to animate their appearance from the point S1.
I would like to insert some sort of If statement of the form "If x>0 then show the circles, else do not show the circle". In other words, I would like my full circles to animate as half circles, but I want to avoid using the CircularArc command.
Can anyone offer some thoughts on how I might go about this?