Falling block duplication using end portals

It's possible to duplicate any sort of falling blocks using end portals, basically, you push/launch the block in the end portal and move it away the moment it's supposed to teleport, that way one falling block will be made on the other side of the portal, whereas the original block didn't teleport.

See https://www.youtube.com/watch?v=fXh5y7Urjxw for a more detailed explenation.

Note: It may be possible to do in survival by launching the blocks from below or above and moving them away at the right moment.