# How to put a big dot (and circle) over a variable?

where one can see a big dot (and circle) over W. I am using \dot{W} and \mathring{W} but seems not big enough.

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\documentclass{article}
\usepackage{accents}
\begin{document}
$\accentset{\bullet}{b}$
\end{document}

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This in fact answered another question of mine: How to write a big dot as in the dot product of vectore? The word 'bullet' reminded me! –  Aneesh Karthik C yesterday