TikZ or symbol eyes for difficulty of examples/exercises

Question

In this time, very busy from June, I'm creating my book of Physics and I'm using some options of the structure.tex of The Legrand Orange Book. I have occurred of your precious help if possible. Into my old MWE (year 2007) with macros, I can put to add my eyes (erre.69, erre.70 etc.) in format .eps files. You can see picture below,

with my source,

\documentclass[a4paper,italian,10pt]{article}
\usepackage{babel}

%occhietti
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\input epsf
\def\ob{\epsfxsize=.28cm\epsfbox{erre.69}}
\def\os{\epsfxsize=.28cm\epsfbox{erre.72}}
\def\od{\epsfxsize=.28cm\epsfbox{erre.73}}
\def\oa{\epsfxsize=.28cm\epsfbox{erre.74}}
\def\oc{\epsfxsize=.28cm\epsfbox{erre.75}}
\def\ov{\epsfxsize=.28cm\epsfbox{erre.76}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


\begin{document}

Different typology of examples or exercises with macros
$\ob,\os, \od,\oa,\oc,\ov$


\end{document}

But I would like to have the same eyes (created with TikZ - I don't remember that exists a symbol for these eyes!) without to use images in .pdf or .eps. format. Infact into my book I'm using many reduce figures only in .pdf. The code below is the same into Legrand Orange Book to create "examples" (for example) is:

\newenvironment{example}{\begin{exampleT}}{\hfill{\tiny\ensuremath{\blacksquare}}\end{exampleT}}.

Is the possibility to create a best \newenvironment {example} and \newenvironment {exercise} exactly to have the same eyes created with TikZ, same size, same command (\ob,\os,\oa, etc.)?

Answer 1

It is very simple to do.

If you get the idea, you can create the other few you want.

The output

The code

\documentclass[12pt]{standalone}
\usepackage{tikz}
\newcommand\straightEye[1][1.2ex]
{%
\begin{tikzpicture}[scale=#1/1cm]
  \draw (0,0) circle (.5);
  \fill (0,0) circle (.25);
\end{tikzpicture}%
}
\newcommand\downwardsEye[1][1.2ex]
{%
\begin{tikzpicture}[scale=#1/1cm]
  \draw (0,0) circle (.5);
  \fill (0,-.25) circle (.25);
\end{tikzpicture}%
}
\newcommand\rightEye[1][1.2ex]
{%
\begin{tikzpicture}[scale=#1/1cm]
  \draw (0,0) circle (.5);
  \fill (.25,0) circle (.25);
\end{tikzpicture}%
}
\begin{document}
\straightEye \downwardsEye \ look at me \rightEye\rightEye
\end{document}

Or like this :

The output

The code

\documentclass[12pt]{standalone}
\usepackage{tikz}
\newcommand\sideEye[2][1.2ex]
{%
\begin{tikzpicture}[scale=#1/1cm]
  \draw (0,0) circle (.5);
  \fill (#2:.25) circle (.25);
\end{tikzpicture}%
}
\begin{document}
\foreach \ang in {0,30,...,360} {\sideEye{\ang}}
\end{document}

Answer 2

I like the answer of marsupilam. For the completeness sake: my idea of reducing the number of images embedded into the pdf file would be to embedd it only once.

Basically save each kind of eyes using a box, then just use these boxes. My current understanding is that the images would be embedded only once and then referenced again and again in the output file.

Update: I was just told than standard boxes don't work like this, but xsavebox does the trick. Thanks to AlexG.