\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amsfonts,amssymb}

\usepackage{tikz}
\usetikzlibrary{shapes,positioning}
\usetikzlibrary{narrow}

\tikzset{block/.style={draw, rectangle, line width=2pt,
     minimum height=3em, minimum width=3em, outer sep=0pt,
     fill=blue!10}}
\tikzset{connector/.style={draw,circle,inner sep=0mm,minimum size=2mm}}
\tikzset{every picture/.style={auto, line width=1pt, x=1mm, y=1mm,
          >=narrow,font=\small}}

\begin{document}

\begin{tikzpicture}
\node[block](Adam){Adam};
\node[connector,left=10mm of Adam](i1){};
\node[connector,left=4mm of i1, yshift=3mm](i2){};
\node[connector,left=4mm of i1, yshift=-3mm](i3){};
\node[block, below=6mm of Adam](Bertil){Bertil};

\draw[->](i1)--(Adam);
\draw[->](Adam.east)--node[xshift=-1mm](YY){$YY$}++(16,0);
\draw[->](YY)|-(Bertil);
\draw[->](Bertil)-|node[near end]{$TT$}(i3);
\draw[](i1)--(i2);
\draw[->](i2) ++(-14,0)--node[near start]{$UU$}(i2);
\end{tikzpicture}
\end{document}