In order to add some chemistry to this list, here is a laboratory duck helping to explain the concept of chirality.

\documentclass{standalone}
\usepackage{tikzducks}
\usepackage{chemfig}
\usepackage{arydshln}
\begin{document}
\colorbox{black!20!white}{
\begin{tabular}{c:c}
\begin{tikzpicture}[xscale=-1,transform shape]
\duck[glasses=gray,tshirt=black!10!white,jacket=white]
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw,clip] (-0.5,1.75) to[rounded corners=2pt]++(0,-1)to[rounded corners=2pt]++(-1,-2.5)to[rounded
corners=2pt, bend right=10pt]++(3,0) to[rounded corners=2pt]++(-1,2.5)--++(0,1)++(-0.5,0) circle [x radius=0.5, y radius=0.1];
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,fill=green!90!black](-1.6,-2) rectangle (1.6,{1cm-2cm});
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,fill=green!90!white] (0,1cm-2cm) circle [x radius=1.5cm-(1cm-0.25cm)*0.4 , y radius=0.1 cm];
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0,0) circle (5pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (-0.2,0.75) circle (3pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0.25,1.15) circle (2pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0,1.4) circle (4pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (-0.25,-0.5) circle (3pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0.25,-1) circle (5pt);
\end{tikzpicture}
&
\begin{tikzpicture}
\duck[glasses=gray,tshirt=black!10!white,jacket=white]
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw,clip] (-0.5,1.75) to[rounded corners=2pt]++(0,-1)to[rounded corners=2pt]++(-1,-2.5)to[rounded
corners=2pt, bend right=10pt]++(3,0) to[rounded corners=2pt]++(-1,2.5)--++(0,1)++(-0.5,0) circle [x radius=0.5, y radius=0.1];
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,fill=green!90!black](-1.6,-2) rectangle (1.6,{1cm-2cm});
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,fill=green!90!white] (0,1cm-2cm) circle [x radius=1.5cm-(1cm-0.25cm)*0.4 , y radius=0.1 cm];
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0,0) circle (5pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (-0.2,0.75) circle (3pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0.25,1.15) circle (2pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0,1.4) circle (4pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (-0.25,-0.5) circle (3pt);
\path[xshift=35,yshift=20,scale=0.2,rotate=-10,draw=black, line width=0.2pt, fill=green!70!white] (0.25,-1) circle (5pt);
\end{tikzpicture}
\\[0.25cm]
\scalebox{0.6}{\chemfig{A-[:30](-[:90]B)(<:[:-10]C)(<[:-50]D)}}
&
\scalebox{.6}{\chemfig{A-[:150](-[:90]B)(<:[:190]C)(<[:230]D)}}
\end{tabular}
}
\end{document}
PS: Thanks to appropriate personal protective equipment (safety glasses and a lab coat) no ducks were harmed during the experiments...
The code for the erlenmeyer flask is heavily inspired frome this question: tikz and \pgfdeclareshape why the text is not at the center anchor?
\let\qed=\duck
gets a duck at the end of every proof. – Andrew Stacey Mar 25 '18 at 16:25quack erat demonstrandum
, isn't it? – samcarter_is_at_topanswers.xyz Mar 25 '18 at 17:26quod erat duck
. – Andrew Stacey Mar 25 '18 at 18:44