# Why won't ball show up? \ball is undefined control sequence

%A.DOCUMENTCLASSes.
%The document class produces a style for the document. %Most papers work fine with the next one.
%For letter style see the letter document on the website.
% For presentations, see a beamer document on the website. %
%\documentclass[10pt]{article}
\documentclass{beamer}
%\documentclass[10pt]{letter}
%The next commands are for latex packages which we sometimes use. %
\usepackage[ansinew]{inputenc}
\usepackage{color}
\usepackage{enumerate,latexsym}
\usepackage{amsmath,amssymb}
\usepackage{graphicx}
\usepackage{amsxtra}
\usepackage{amsfonts}
\usepackage{enumitem}
\usepackage{amsthm}
\usepackage{showkeys}
\usepackage{paralist}
%COMMENT: The next 2 software packages are only for presentations. %
%C. PAGE LAYOUT.
%The following commands are not for presentations!
%These commands are for creating margins, text width, text length %and double spacing for papers.
%
%\setlength{\oddsidemargin}{10pt} \setlength{\evensidemargin}{10pt} %\setlength{\textwidth}{430pt}
%\textwidth 15cm
%\oddsidemargin .2cm \evensidemargin .2cm
%\textheight 20cm
%\topmargin -.3cm
%\renewcommand{\baselinestretch}{2}
%D.COLORS.
%These commands are for colors for papers and presentations. %Note that \rrr makes RED, %\bbb makes BLUE,
%\ppp makes PURPLE and \ggg makes GREEN.
\definecolor{b}{rgb}{.1,.1,.7}
\definecolor{rr}{rgb}{.8,0,.3}
\definecolor{g}{rgb}{0,.5,0}
\definecolor{pp}{rgb}{.5,0,.7}
%E.ABBREVIATIONS.
%The next commands are abbreviations used frequently % especially in multi-variable calculus.
%
%F.NEGATIVE SPACE
%G. NUMBERED THEOREMS, DEFINITIONS,...
%These commands are for papers only.
%(for presentations, they need to be commented out).
%They create numbered theorems and other numbered objects like definitions % The section'' part produces numbering by section.
%If you remove that part, then the section number %where the "theorem" is located will not appear
%in the numbering of the statement of the "theorem". %
%\newtheorem{theorem}{Theorem}[section] \newtheorem{definition}[theorem]{Definition} %\newtheorem{definition}{Definition}[section]
%G'.
%Some commands mostly for presentations. %
%\newtheorem{conjecture}{Conjecture}
%\newtheorem{history}{\large History}
%\newtheorem{question}[theorem]{Question}
%\newtheorem{Case}{Case}
%\newtheorem{notation}{Notation}
%H.SHORTHANDS \def and \newcommand.
%The command \def is used create abbreviations for
%frequently used symbols like the math symbol for capital R
%that we use to denote the real numbers or the Greek letter theta.
%For longer abbreviations or commands, we usually use the command %\newcommand. For example, %instead of typing \end{document}
%It may not be a good idea to use too many of
%these abbreviations if someone else (a coauthor) is
\def\R{\mathbb{R}}
\def\t{\theta}
\def\rth{\mathbb{R}^3}
\newcommand{\ben}{\begin{enumerate}}
\newcommand{\bit}{\begin{itemize}}
\newcommand{\een}{\end{enumerate}}
\newcommand{\eit}{\end{itemize}}
\newcommand{\ed}{\end{document}}
%X. GRAY shaded BLOCKS in presentations.
%The next 2 commands are for creating gray shaded blocks in presentations.
\newcommand{\bblock}{\begin{block}}
\newcommand{\eblock}{\end{block}}
\setbeamertemplate{itemize items}[ball]
\begin{document}
\begin{frame}
\begin{exampleblock}{Example (This is a very popular midterm exam problem)}
Find an \textcolor{b}{equation of the plane} which contains the points \\
$P(-1,2,1)$, $Q(1,-2,1)$, and $R(1,1,-1)$.
\end{exampleblock}
\begin{block}{Solution:}
{\bf\Large Method 1.}\\
\begin{itemize}
\item[\ball] 1
\item[\ball] 2
\item[\ball] 3
\end{itemize}
\end{block}
\end{frame}
\end{document}

-
There is no \begin{block} to go with \end{block}. If you remove all the irrelevant material from your code, the error is easy to find. –  Ian Thompson Apr 15 '14 at 21:52
Suggested reading: minimal working example (MWE) –  Jubobs Apr 15 '14 at 22:01
Remove the line \end{block}. Also, take into account that \bfseries (never use \bf in LaTeX documents) and \Large are font switches and not commands with arguments, so you have to use {\bfseries\Large text} and not \bfseries\Large{text}. –  Gonzalo Medina Apr 15 '14 at 22:02
I need a block in there, I got it to run but for some reason the items are not showing up and the bold and large are running through the items. I also keep getting method 1 on the top left corner –  steph Apr 15 '14 at 22:02
@steph You already have an exampleblock. –  Gonzalo Medina Apr 15 '14 at 22:06

1. You had \end{block} without \begin{block}{}. Notice the pair of braces after \begin{block}; those are used for an eventual title for the block; if empty, no title is added.

2. Don't load the enumitem package with beamer. The beamer class has its own way to handle lists and enumitem will interfere with the beamer settings producing undesired results like the one you experienced.

3. Take into account that \bfseries (never use \bf in LaTeX documents) and \Large are font switches and not commands with arguments, so you have to use {\bfseries\Large text} and not \bfseries\Large{text}.

4. You are loading some packages that beamer already loads internally: amsmath, amsthm, graphicx, color. You can suppress the lines loading them form your code.

The code:

%A.DOCUMENTCLASSes.
%The document class produces a style for the document. %Most papers work fine with the next one.
%For letter style see the letter document on the website.
% For presentations, see a beamer document on the website. %
%\documentclass[10pt]{article}
\documentclass{beamer}
%\documentclass[10pt]{letter}
%The next commands are for latex packages which we sometimes use. %
\usepackage[ansinew]{inputenc}
\usepackage{latexsym}
\usepackage{amssymb}
\usepackage{amsxtra}
%COMMENT: The next 2 software packages are only for presentations. %
%C. PAGE LAYOUT.
%The following commands are not for presentations!
%These commands are for creating margins, text width, text length %and double spacing for papers.
%
%\setlength{\oddsidemargin}{10pt} \setlength{\evensidemargin}{10pt} %\setlength{\textwidth}{430pt}
%\textwidth 15cm
%\oddsidemargin .2cm \evensidemargin .2cm
%\textheight 20cm
%\topmargin -.3cm
%\renewcommand{\baselinestretch}{2}
%D.COLORS.
%These commands are for colors for papers and presentations. %Note that \rrr makes RED, %\bbb makes BLUE,
%\ppp makes PURPLE and \ggg makes GREEN.
\definecolor{b}{rgb}{.1,.1,.7}
\definecolor{rr}{rgb}{.8,0,.3}
\definecolor{g}{rgb}{0,.5,0}
\definecolor{pp}{rgb}{.5,0,.7}
%E.ABBREVIATIONS.
%The next commands are abbreviations used frequently % especially in multi-variable calculus.
%
%F.NEGATIVE SPACE
%G. NUMBERED THEOREMS, DEFINITIONS,...
%These commands are for papers only.
%(for presentations, they need to be commented out).
%They create numbered theorems and other numbered objects like definitions % The section'' part produces numbering by section.
%If you remove that part, then the section number %where the "theorem" is located will not appear
%in the numbering of the statement of the "theorem". %
%\newtheorem{theorem}{Theorem}[section] \newtheorem{definition}[theorem]{Definition} %\newtheorem{definition}{Definition}[section]
%G'.
%Some commands mostly for presentations. %
%\newtheorem{conjecture}{Conjecture}
%\newtheorem{history}{\large History}
%\newtheorem{question}[theorem]{Question}
%\newtheorem{Case}{Case}
%\newtheorem{notation}{Notation}
%H.SHORTHANDS \def and \newcommand.
%The command \def is used create abbreviations for
%frequently used symbols like the math symbol for capital R
%that we use to denote the real numbers or the Greek letter theta.
%For longer abbreviations or commands, we usually use the command %\newcommand. For example, %instead of typing \end{document}
%It may not be a good idea to use too many of
%these abbreviations if someone else (a coauthor) is
\def\R{\mathbb{R}}
\def\t{\theta}
\def\rth{\mathbb{R}^3}
\newcommand{\ben}{\begin{enumerate}}
\newcommand{\bit}{\begin{itemize}}
\newcommand{\een}{\end{enumerate}}
\newcommand{\eit}{\end{itemize}}
\newcommand{\ed}{\end{document}}
%X. GRAY shaded BLOCKS in presentations.
%The next 2 commands are for creating gray shaded blocks in presentations.
\newcommand{\bblock}{\begin{block}}
\newcommand{\eblock}{\end{block}}

\begin{document}

\begin{frame}
\begin{exampleblock}{Example (This is a very popular midterm exam problem)}
Find an \textcolor{b}{equation of the plane} which contains the points \\
$P(-1,2,1)$, $Q(1,-2,1)$, and $R(1,1,-1)$.
\end{exampleblock}
\begin{block}{Solution:}
{\bfseries\Large Method 1.}
\begin{itemize}
\item First.
\item Second.
\end{itemize}
\end{block}

\end{frame}

\end{document}


-
I don't want the format of the blocks to be like this I want it to be the way I have it. I just want ball to show up:\setbeamertemplate{itemize items}[ball] \begin{document} \begin{frame} \begin{exampleblock}{Example (This is a very popular midterm exam problem)} Find an \textcolor{b}{equation of the plane} which contains the points \\ $P(-1,2,1)$, $Q(1,-2,1)$, and $R(1,1,-1)$. \end{exampleblock} \begin{block}{Solution:} {\bf\Large Method 1.}\\ \begin{itemize} \item[] 1 \item[\ball] 2 \item[\ball] 3 \end{itemize} \end{block} \end{frame} \end{document} –  steph Apr 15 '14 at 22:17
@steph Please see my updated answer. I gave you two options for the block and also solved the problem with the itemize. –  Gonzalo Medina Apr 15 '14 at 22:18
OMG thank you so much!! –  steph Apr 15 '14 at 22:21