\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{ifthen}
\usepackage{multicol}

\newcommand{\multiples}[4]{%

  \ifthenelse{\isundefined{\thekolik}}
     { \newcounter{kolik} }
     {}   
  \setcounter{kolik}{1}
  #3
  \bigskip
  
  \whiledo{\value{kolik} < \numexpr#1+1}{%
    \textbf{sazba \arabic{kolik}}: #2
    \par
    \medskip
    \stepcounter{kolik}
    }
  \bigskip
  #4
}

\newenvironment{doublecol}
               { \begin{center}
                   \begin{minipage}{0.9\textwidth}
                     \begin{multicols}{2}
                       \raggedright
                       \footnotesize
                       
               }
               %
               {
                     \end{multicols}
                   \end{minipage}
                 \end{center}
               }
                 
  

\begin{document}

\paragraph{Úkol 1} \emph{procvičení definice nového makra, použití cyklu a
  podminky, definice a inkrementování nového čítače, kontrola
  existence čítače, aritmetika v podmince (napoveda: $\backslash$numexpr)  }

Naprogramujte nové makro \verb!\multiples! beroucí 4 parametry. Makro
se musí dát použít opakovaně! Příklad použití
\begin{verbatim}
\multiples{3} 
{Call me Ishmael. Some years ago never 
 mind how long precisely having little 
 or no money in my purse, and nothing
 particular to interest me on shore, 
 I thought I would sail about a
 little and see the watery part of the world.}  
 {Zacatek} 
 {Konec}
\end{verbatim}

\bigskip

\multiples{3}{Call me Ishmael. Some years ago never mind how long precisely having
  little or no money in my purse, and nothing particular to interest
  me on shore, I thought I would sail about a little and see the
  watery part of the world.}
 {Zacatek}{Konec}

\newpage

\paragraph{Úkol 2} Definujte nové prostředí, které bude
sázet svůj obsah dvousloupcově, písmem o velikosti footnotesize,
se zarovnáním vlevo a šířkou textu užší
než šířka zbylého textu (v příkladu je to 90 procent šířky textu).
\emph{Nápověda: prostředí minipage}

\begin{doublecol}

  Call me Ishmael. Some years ago—never mind how long precisely—having
  little or no money in my purse, and nothing particular to interest
  me on shore, I thought I would sail about a little and see the
  watery part of the world. It is a way I have of driving off the
  spleen and regulating the circulation. Whenever I find myself
  growing grim about the mouth; whenever it is a damp, drizzly
  November in my soul; whenever I find myself involuntarily pausing
  before coffin warehouses, and bringing up the rear of every funeral
  I meet; and especially whenever my hypos get such an upper hand of
  me, that it requires a strong moral principle to prevent me from
  deliberately stepping into the street, and methodically knocking
  people's hats off—then, I account it high time to get to sea as soon
  as I can. This is my substitute for pistol and ball. With a
  philosophical flourish Cato throws himself upon his sword; I quietly
  take to the ship. There is nothing surprising in this. If they but
  knew it, almost all men in their degree, some time or other, cherish
  very nearly the same feelings towards the ocean with me.

  There now is your insular city of the Manhattoes, belted round by
  wharves as Indian isles by coral reefs—commerce surrounds it with
  her surf. Right and left, the streets take you waterward. Its
  extreme downtown is the battery, where that noble mole is washed by
  waves, and cooled by breezes, which a few hours previous were out of
  sight of land. Look at the crowds of water-gazers there.
\end{doublecol}

Text za prostředím opět pokračuje normálně. There now is your insular
city of the Manhattoes, belted round by wharves as Indian isles by
coral reefs commerce surrounds it with her surf. Right and left, the
streets take you waterward. Its extreme downtown is the battery, where
that noble mole is washed by waves, and cooled by breezes, which a few
hours previous were out of sight of land. Look at the crowds of
water-gazers there.

\end{document}

