Creating a dynamic numbered list in InDesign with individual, unchained text blocks

You can do this with automatic numbering and lists.

https://creativepro.com/setting-up-numbered-lists-that-jump-frames-in-cs3/

But keep in mind that the order is defined by the creation order of the frame and not by its position on the page.

If just by their location - by rows & columns - it would be fairly easy. 

TextFrames should either be on a separate layer or have the same label / ObjectStyle applied. 

Maybe it's not rocket surgery in that you could pretty easily code a simple app that does this — in some ways, it's just a simple puzzle game sort of model — but I can't think of any way that InDesign handles numbering that meshes with the idea.

Unless I'm overlooking some subtle feature, or not giving enough credit to scripting possibilities, ID numbers paragraphs by their order in text flow. You could break each paragraph into its own text frame, and move those frames around, but ID threads them by the order in which they are created. So you could move Block #3 anywhere on the page, above or below or to the left or right of any other block, and ID is always going to see it as Block #3 and number the contents following whatever is in Block #2.

ID is a powerful tool, but it's not really strong on realtime dynamic content like this autonumbering would require.