Drawing a Box

Try it.
%!
%% Draws a one square inch box and inch in from the bottom left

/inch {72 mul} def	% Convert inches->points (1/72 inch)

newpath			% Start a new path
1 inch 1 inch moveto	% an inch in from the lower left
2 inch 1 inch lineto	% bottom side
2 inch 2 inch lineto	% right side
1 inch 2 inch lineto	% top side
closepath		% Automatically add left side to close path
stroke			% Draw the box on the paper
showpage		% We're done... eject the page