% TeX root = ../main.tex
\begin{tikzpicture}
\node[state,initial] (l0) ;
\node[state] (l1) [below=2cm of l0] ;
\node[state] (l2) [below=3cm of l1] ;
\path[->]
(l0) edge node (l1)
(l1) edge [out=150,in=210,looseness=10] node[swap] (l1)
(l1) edge[bend left =30] node (l2)
(l2) edge[bend left=30] node (l1)
% (l1) edge node {$t_4:x \leq 0$} (l2)
% edge[loop above] node {$t_2:\begin{aligned} x &> 1 \\ x&:=
% x+1\end{aligned}$} ()
% edge[loop below] node {$t_3:\begin{aligned} x &> 0 \\ x&:=
% x-1\end{aligned}$} ()
;
\end{tikzpicture}