% figures
% Create \savelength to use in saving and restoring \unitlength
%    just in case some other value is being used between diagrams
\newlength{\PGsavelength}

% \PGset saves current \unitlength in \PGsavelength, and sets \unitlength to {arg}
\newcommand{\PGset}[1][\unitlength]{\setlength{\PGsavelength}{\unitlength}\setlength{\unitlength}{#1}}

% \PGrestore sets \unitlength back to the value saved in \PGsavelength
\newcommand{\PGrestore}{\setlength{\unitlength}{\PGsavelength}}
