This script was found on the temple walls of the Thanjavur <a href="https://en.wikipedia.org/wiki/en:Brihadeeswarar_Temple" class="extiw" title="w:en:Brihadeeswarar Temple">Thanjavur Brihadeeshwarar temple</a>. This is very different from the present Tamil script.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/79243450@N00">Symphoney Symphoney</a> from New York, US
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/79243450@N00/76513801/">Ancient Tamil Script</a>