< But unfortunately difficult to write in the form of an algorithm.
So for ovoid that must be name all thing and selection will be more easy :)

Another thing : a selection by "Array" ?
so in this case you select a little circle (so circle is the "circle box selection" ) and apply a "circular array selection" ;)
(like the function Array circular)
Or you select an "aera box" and apply the "Array selection"