\documentclass[11pt,leqno]{article}

\newcommand{\pathtotrunk}{./}
\input{preamble}
\input{text/article_preamble}
\input{text/kw_macros}

%\title{Blob Homology}
\title{Sandbox}
\begin{document}

\newcommand{\vertex}{node[circle,fill=black,inner sep=1pt] {}}

\begin{tikzpicture}
\coordinate (P) at (0,0);
\coordinate (Q) at (3,0);
\coordinate (R) at (1.5,-0.5);
\draw (P) \vertex to[out=40,in=140] node[above] {$a$} (Q) \vertex -- node[below] {\scriptsize $y \times I$} (R) \vertex to[out=-180,in=-40] node[below] {$a$} (P);
\clip (P) to[out=40,in=140] (Q) -- (R) to[out=-180,in=-40] (P);
\foreach \x in {1,...,9} {
	\path (P) to[out=40,in=140] node[pos=\x/10] (PQ\x) {} (Q);
	\path (P) to[out=-40,in=-180] node[pos=\x/10] (PR\x) {} (R);
	\draw[green!50!brown] (PQ\x.center) -- (PR\x.center);
}
\end{tikzpicture}

\begin{tikzpicture}
\node[circle,fill=black,inner sep=1pt] (A) at (1.73,0) {};
\node[circle,fill=black,inner sep=1pt] (B) at (-1.73,0) {};
\draw[dashed] (A) -- (B);
\node[circle,fill=black,inner sep=1pt] (C) at (0,0) {};
\node[circle,fill=black,inner sep=1pt] (D) at (0.8,0) {};
\begin{scope}[yshift=-1cm]
\path[clip] (0,0) circle (2);
\begin{scope}[yshift=2cm]
\draw (0,0) circle (2);
\node[circle,fill=black,inner sep=1pt] (L2) at (-90:2) {};
\node[circle,fill=black,inner sep=1pt] (L1) at (-120:2) {};
\end{scope}
\end{scope}
\begin{scope}[yshift=1cm]
\path[clip] (0,0) circle (2);
\begin{scope}[yshift=-2cm]
\draw (0,0) circle (2);
\node[circle,fill=black,inner sep=1pt] (U) at (90:2) {};
\end{scope}
\end{scope}
\begin{scope}
\path[clip] (0,1) circle (2);
\path[clip] (0,-1) circle (2);

\end{scope}
\end{tikzpicture}
\end{document}