Word does not have that facility. For text constraining purposes, all shapes
are considered rectangular.
You can achieve the effect - to a certain extent - by setting the octagon to
be behing the text and by adding some extra shapes - thin rectangles of
differing lengths - outside the octagon and setting them to have text
wrapped around them. It is a bit fiddly, though!
Expanding on Tony's workaround a bit, you can use both rectangle shapes
along the sides and triangle shapes at the diagonal corners with Tight
wrapping to push the text into an octagon. See http://jay-freedman.info/triangle_text.doc for an example of the technique.
--
Regards,
Jay Freedman
Microsoft Word MVP
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