I want to add the symbol of the end of a proof in a beamer frame as it is shown in the following picture
I try as follows
\documentclass[xcolor=dvipsnames]{beamer}
\usepackage{pifont}
\mode<presentation>
\usetheme{Madrid}
\begin{document}
\begin{frame}{Sketch of Proof}
The steps of our theorem are the following:
\textcolor[rgb]{1.00,0.00,1.00}{\ding{228}} ....
\textcolor[rgb]{1.00,0.00,1.00}{\ding{228}} ....
\textcolor[rgb]{1.00,0.00,1.00}{\ding{228}} ....
\textcolor[rgb]{1.00,0.00,1.00}{\ding{228}} ....
\[ \qedhere\]
\end{frame}
\end{document}