This seems enormously indeterminate to me. The phrase "sort aleatory or whatever" [aleatory essentially means "random"] is especially problematic. Assuming the insertion points would be the basis of positioning inside the shape, a really random distribution could give you a result like this:

I assume that would not be an acceptable outcome.
I think you would need to consider carefully what is needed, what the likely conditions would be, and spell out some definite criteria that would limit the possibilities. Should they be placed no less than a certain distance from the perimeter? No less than a certain distance from each other? Do those certain distances depend on the size of the Blocks? Do they depend on the size of the perimeter? For example, with distance-from-perimeter and distance-from-each-other limits, without consideration of the size of the perimeter, you could get a result like this:

which I assume would also be undesirable.
If the Blocks are not "compact" shapes and their insertion points are not at least close to the middle, would the distances need to be affected by each Block's rotation angle? Would the selection always be multiple copies of the same Block, or could they be different ones? If different, would they at least be of approximately the same size? Etc., etc.
I don't think it is a simple task -- it might be fairly easy if the shapes are always Circles or Ellipses or Rectangles [or at least fully convex closed Polylines with relatively low numbers of vertices], but for a shape similar to the later ones in your images [yellow above], calculating the appropriate locations inside it could be very difficult.
Kent Cooper, AIA