\chapter{Easy Flashcards in \LaTeX{} }

\section{Introduction}

I was a biology major in college (the first time around, that is) and so I had to memorize \textit{lots} of information. 

\kdivb{Is it worth it?}{3}
A sidebar debate of the usefulness of memorizing anything.
\kdive{3}

One of the best ways I've found to memorize information is to use flash cards. As I see it, flash cards have three main advantages. First, you have to write this information onto the flash cards, so you have yet another opportunity to review the information. (I tend to learn better by reading and writing than by listening.) Second, because you to fit the information on an index card, you have to edit the information, which is yet another opportunity to process the information. Third, because each bit of information is on a separate card, you can easily sort these cards as you study them, gradually setting aside the cards you know, so that you can focus on the material you still need to learn. 

Unfortunately, flash cards are a lot of work to make. (You can buy commercial versions, but they are expensive and may not suit your exact purposes.) Because you have to make them by hand, you're essentially a medieval scribe, copying a text very laboriously by hand. It's not a fun process for most people.\footnote{I will admit to being an exception here.}

Fortunately, \LaTeX{} has a number of packages that make the production of flash cards a fairly simple process.  

\subsection{Online Examples}

I had a lot of fun playing around with these packages, and have created a number of example documents for you to download and play around with. I've posted these to both my personal git repository and Codeberg. You can see them here: 

\begin{itemize}
\item \textbf{Personal:} \kref{https://git.kjodle.net/kjodle/flashcard-examples}{https://git.kjodle.net/kjodle/flashcard-examples}
\item \textbf{Codeberg:} \kref{https://codeberg.org/kjodle/flashcard-examples}{https://codeberg.org/kjodle/flashcard-examples}
\end{itemize}

\section{The \textsf{FlashCards} Package}

The \textsf{FlashCards} package (and note that it is written in CamelCase) allows you to easily create flashcards and then print them on standard sheet-fed business-card stock which is equivalent to Avery 5371.\footnote{This is for North American business-card stock, which is 8.5 $\times$ 11 inches.} (Avery products are pretty expensive, but I can usually find a less expensive off-brand version elsewhere.)

\textsf{FlashCards} offers you a limited set of options, which is just fine, since it's more about the information on these cards, rather than how they look. Flash cards don't need to be fancy, but you can do a certain amount of customization with this package. 

The truly nice thing about the \textsf{FlashCards} package is that it automatically sets up the cards for two-sided printing. That is, if the front of your document looks like this:

\begin{center}
	\begin{tikzpicture}[scale=0.6]
		\draw (0,0) rectangle (11,4);
		\draw (1,1) rectangle (5,3);
		\node at (3,2) {{\Huge A}};
		\draw (6,1) rectangle (10,3);
		\node at (8,2) {{\Huge B}};
	\end{tikzpicture}
\end{center}

\noindent{}then the back of your document needs to look like this for the cards to print properly:

\begin{center}
	\begin{tikzpicture}[scale=0.6]
		\draw (0,0) rectangle (11,4);
		\draw (1,1) rectangle (5,3);
		\node at (3,2) {{\Huge B}};
		\draw (6,1) rectangle (10,3);
		\node at (8,2) {{\Huge A}};
	\end{tikzpicture}
\end{center}

This way, the back of card A and front of card A will appear on opposite sides of the same card.\footnote{This is an incredibly difficult concept for some people to understand. (If you don't beleive me, just ask anyone who's ever worked in a copy shop.) Some people just have a lot of trouble re-orienting three-dimensional ojbects in their mind. I have a funny feeling that these are the people who just never got to build anything when they were children, or who never got to play with building toys like Lego or Tinker Toys.}

\subsection{Using the \textsf{FlashCards} Package}

The \textsf{FlashCards} package defines a new document class (called, natch, ``\texttt{flashcards}'') with one required option and a few non-required options. The first option is the type of Avery cardstock you will be printing your cards on. Out of the box, it only supports business cards (Avery 5371) and index cards (Avery 5388) but it is easy enough to configure your own, which we'll see in a bit. 

The non-required options include \texttt{fronts} and \texttt{backs} for typesetting only the fronts or backs of your cards, \texttt{grid} to draw lines where the perforations are (which is handy if you are printing on non-perforated card stock, because you can just cut them apart on the lines), and \texttt{frame} to draw a frame around the content of each card. 

\textsf{FlashCards} defines a new environment (\texttt{flashcard}) with a single required argument, which is the text on the front of the card. Anything contained within the environment (which can include both math and \texttt{tikz} drawings) goes on the back of the card, like so:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{FlashCards example}]
\begin{flashcard}[]{This is the front of the card}
This is the back of the card
\end{flashcard}
\end{Verbatim}

The argument contained in square brackets (which are empty in our example) allows you to add a header to the card, which will only appear if you used the \verb|\cardfrontstyle{headings}| command. This allows you to describe some cards in your flash card deck according to what they are (definition, formula, etc.). If you then use the \verb|\cardfrontfoot{<text>}| you can define a footer that will appear on \textit{every} card in your document (e.g. Biology 101).

You do have some options for modifying how the headers are footers are typeset, which is described clearly in the package documentation. You can also look at the sample files I've posted online for other examples.

\subsection{Having Fun with \textsf{FlashCards}}

When I first set up my own Git repo, one of the first things I did was add a list of the Ferengi Rules of Acquisition. When I started playing around with flash cards in \LaTeX{} I didn't really have anything I was studying at the time, so I decided to use the Rules as an example. However, there were a couple of issues I wanted to see if the \textsf{FlashCards} package could deal with.

The first is that I wanted the front side of the card to be in a unique font. That is, I wanted it to be something that didn't scream ``LaTeX'' when people saw it. The second is that the rules are numbered, and I have no desire to add all those numbers by hand, so I wanted to see how easy it was to use a counter with this package. 

The first thing to do was to add a new font. I looked around and liked the ``Roman Rustic'' font,\footnote{Which you can see at \kref{https://tug.org/FontCatalogue/romanrustic/}{https://tug.org/FontCatalogue/romanrustic/}.} so I added these lines to my preamble: 

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, ]
% Font for front side of cards
% Use \rustfamily to apply font
\usepackage{rustic}
\usepackage[T1]{fontenc}

\cardfrontstyle[\large\itshape\bfseries\rustfamily]{headings}
\cardbackstyle{plain} % plain option centers text
%\cardfrontfoot{Rules of Acquisition}
\end{Verbatim}

Lines 3 and 4 add our font\footnote{Notice that I also added comments on lines 1 and 2 regarding what this was and how to use them. I am not going to remember this next week, much less a year from now. Comments are free. Use them often.} and line 5 applies it to the card front. That line also says that we are going to use the \texttt{headings} option, although I decided not to when wetting up the actual cards. 

I experimented with various fonts, and some of them contained a hash character (\#) and some of them did not. So I added a macro that would allow me to easily change that, based on the font. 

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, ]
% A new command in case we want to separate what we use to indicate 'number'
% May need to change this based on the font
\newcommand{\ksep}{\\ \vspace{5mm} No.}
\end{Verbatim}

(Is this a hack? No, not really. It's more of a kludge than anything else. Sometimes the thing you need is just a good hard slash through the Gordian knot of your current situation.)

I then needed to add my counter, which I did with 

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, ]
\newcounter{rule}
\setcounter{rule}{1}
\end{Verbatim}

I then started adding my cards, making sure to increment the counter after each card:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Rules of Acquisition FlashCards exampleS}]
\begin{flashcard}[]{Rule of Acquisition \ksep \arabic{rule}}
Once you have their money, you never give it back.
\end{flashcard}
\addtocounter{rule}{1}
\end{Verbatim}

Compiling that document gave me these beautiful flash cards:

\begin{center}
\includegraphics[scale=0.25]{roa-card-front} \hspace{10mm} \includegraphics[scale=0.25]{roa-card-back}
\end{center}

You can see the full file in either the repos I mentioned earlier.

\subsection{Modifying the \textsf{FlashCards} Configuration Files}

There's just one catch with the FlashCards package: it only includes support for business cards and $3\times5$ index cards. The documentation says that variants are easy to generate, so there has to be a way to do that, right? As it turns out, there is. The first step is to find those configuration files. 

The first step is to find those configuration files. We have a couple of options here. The first is to look in the \texttt{.log} file of any project we've used the \texttt{flashcards} package. Looking at my ``Rules of Acquisition'' log file showed me this on line 9: 

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Location of FlashCards class file}]
(/usr/share/texlive/texmf-dist/tex/latex/flashcards/flashca rds.cls
\end{Verbatim}

and this on lines 41-43:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Location of FlashCards configuration file}]
(/usr/share/texlive/texmf-dist/tex/latex/flashcards/avery537 1.cfg
File: avery5371.cfg 
)
\end{Verbatim}

If we're on the command line, we could also the \texttt{kpsewhich} command to look for the package name \texttt{.cls} file, like this: 

\input{include/kpsewhich}

which gives us this output:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Output of kpsewhich Command}]
ls
/usr/share/texlive/texmf-dist/tex/latex/flashcards/flashcar ds.cls
\end{Verbatim}

Since I don't want to poke around in my default \texttt{/usr} directory (which would require \texttt{sudo} and is not something that can be backed up easily), the solution is to use our own \texttt{texmf} directory, where we can install our own packages and make modifications to them easily.\footnote{See \S 7.1.2 ``Method \#2'' in issue \#3 for more information.}

I already had that folder, so I duplicated the file path (\texttt{/tex/latex/flas\\hcards}) there, copied over the \texttt{avery5371.cfg} file, and renamed it to \texttt{avery5389.cfg}, which is the format for a 2-up $4\times6$ index card, and opened it up for editing. 

The first thing I did was to do a quick search and replace, swapping out ``5389'' for ``5371''. The second thing I did was to change the relevant lines in the config file to fit the $4\times6$ card format. So I changed all of these lines:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Configuration for Avery 5371 Stock}]
\newcommand{\cardpapermode}{portrait}
\newcommand{\cardpaper}{letterpaper}
\newcommand{\cardrows}{5}
\newcommand{\cardcolumns}{2}
\setlength{\cardheight}{2.0in}
\setlength{\cardwidth}{3.5in}
\setlength{\topoffset}{0.50in}
\setlength{\oddoffset}{0.75in}
\setlength{\evenoffset}{0.75in}
\end{Verbatim}

to have these values:

\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Configuration for Avery 5389 Stock}]
\newcommand{\cardpapermode}{portrait}
\newcommand{\cardpaper}{letterpaper}
\newcommand{\cardrows}{2}
\newcommand{\cardcolumns}{1}
\setlength{\cardheight}{4.0in}
\setlength{\cardwidth}{6.0in}
\setlength{\topoffset}{1.5in}
\setlength{\oddoffset}{1.25in}
\setlength{\evenoffset}{1.25in}
\end{Verbatim}

I then saved the file and closed it.

The only thing left to do was to inform \TeX{} about this new file by running 

\input{include/mktexlsr}

I then changed the first line of my ``Rules of Acquistion'' flashcards project to 

\begin{Verbatim}[]
\documentclass[avery5389,grid]{flashcards}
\end{Verbatim}

I re-compiled the project, and indeed, I now had the Ferengi Rules of Acquistion on $4\times6$ index cards! Easy-peasy!

\section{The flacards Package}

\section{The elzcards Package}