\hypersetup{colorlinks,
  linkcolor={blue!50!black},
  citecolor={blue!50!black},
  urlcolor=blue
}

\def\blue{\color{blue}}
\def\red{\color{red}}

\def\webnote{{\sl Video, handout, links at \url{drorbn.net/mc21}}}

% http://tex.stackexchange.com/questions/12895/overlay-symbol-with-another :
\def\s#1{{%
  \setbox0\hbox{#1}%
  \rlap{\hbox to \wd0{\hss$\boldsymbol\mid$\hss}}\box0
}}

\def\Theorem{\raisebox{2.5mm}{\parbox[t]{3.25in}{
{\red Theorem.} There are precisely 17 patterns with which to tile the
plane, no more, no less. They are all made of combinations of the 10
basic features, {\red 2}, {\red 3}, {\red 4}, {\red 6}, {\red \s2}, {\red \s3},
{\red \s4}, {\red \s6}, {\red  M}, and {\red G}, as follows:
}}}

\def\Da{{\red\bf 2222}}
\def\Db{{\red\bf 333}}
\def\Dc{{\red\bf 442}}
\def\Dd{{\red\bf 632}}
\def\De{{\red\bf \s2\s2\s2\s2}}
\def\Df{{\red\bf \s3\s3\s3}}
\def\Dg{{\red\bf \s4\s4\s2}}
\def\Dh{{\red\bf \s6\s3\s2}}
\def\Di{{\red\bf 4\s2}}
\def\Dj{{\red\bf 3\s3}}
\def\Dk{{\red\bf 2\s2\s2}}
\def\Dl{{\red\bf 22M}}
\def\Dm{{\red\bf MM}}
\def\Dn{{\red\bf MG}}
\def\Do{{\red\bf GG}}
\def\Dp{{\red\bf 22G}}
\def\Dq{{\red $\mathbf\emptyset$}}

\def\cm{{\blue$\checkmark$}}

\def\fgr{{free {\red g}lide-reflection}}
\def\fmr{{free {\red m}irror-reflection}}

\def\p{\fontspec{Andy Bold}}
\def\p{\sl}
