Create different shapes of the same objects with its content I was trying to recreate the following screenshot from https://www.youtube.com/watch?v=IzL5GjFjcbU

The cells are quite different from each other and also their content (not visible in the pic) is animated and also variate from cell to cell.
They seem also arranged in an array, but somehow they fit in between the blood vessels. I can get an array of cells that variate but not this complicated. Also external cells are bigger than the internal part.
By using a displace modifier you can obtain subtle variations but not dramatic change in shapes so that they can fill the space nicely.
I don't think they did it manually.
My question is how can this be achieved in Blender? Do you need some python scripting to obtain something like that? I am wondering what's the workflow to do it.
Thanks!
Here is the result after particle emitter suggestion:
I would use a particle system. Here's one approach

Create a circle
Extrude it and scale the extrusion inward to the same radius as the base of the thing that is going up
add a lot of edge loops.
Then I would select all of the faces and delete &quot;faces only&quot;

This will create a circle with a lot of vertices.  
Next I would create a collection of objects representing the cells.  (For my example I only created a cube)
Next I would create a particle system for the circle.

Set it to hair.
Emit from vertices.
Disable random order
Set the number to match the vertices
Render as collect (object in my example)
Use the collection of cells (cube) as the collection (object)


Finally you can use a vertex group to limit which vertices so you can draw the veins where the vertices won't have cells.
My result is too rigid but you can randomize the vertices a bit and so on.
You get about half the work done automatically this way but you have to do the rest to make it organic in any way.