CAD tip # 13737:

An example of such a block ("Lead0") can be found in the sample DWG drawing FmtBlk.dwg - see Block 22544 for download. This block displays the formatted value of the current rotation angle. Similarly, a distance parameter, number of elements, etc. can be used. To align the resulting text, it would be neccessary to move the text position, e.g. by using another lookup table.

The use of the dynamic Lead0 block is then illustrated in the video:

The video also uses the "trick" of automatic update of the text field value (so no manual regeneration of the drawing is required). The LISP reactor is used for this, which updates the fields after each block grip edit. However, it is not suitable for larger drawings (performance). To activate it, load the following LISP code (via .LSP file or by copying it to the command line or to ACADDOC.LSP):

;Auto-update block fields after grip edit
(vl-load-com)
(if (not autoUpFldReactor)(setq autoUpFldReactor (VLR-Command-Reactor nil '((:VLR-commandEnded . autoUpFldCB)))))
(princ "\nBlock grip reactor active")

(defun autoUpFldCB (reactor objectlist / sset blk)
 (if (= (car objectlist) "GRIP_STRETCH")
  (progn
   (if (setq sset (ssget "_I" '((0 . "INSERT")(2 . "`*U*"))))
    (setq blk (ssname sset 0))
   )
   (if blk
    (vla-SendCommand (vla-get-activedocument (vlax-get-acad-object)) "_UPDATEFIELD ")
   )
  )
 )
)
(princ)