\tikzstyle{mybox} =
[
   scale=1,
   minimum height=0.75cm,
   rectangle,
   rounded corners,
   text centered,
   draw=black,
   font={\small}
]
\tikzstyle{arrow} =
[
   -latex,
   thick
]
      
%Distance between lines in diagram
\pgfmathparse{1.25} \let\h\pgfmathresult

%Half of the textheight in mybox
\pgfmathparse{0.375}  \let\dy\pgfmathresult
