If you need an arrangement of figures other than a regular rectangular array, you must specify the origin and size for each plot manually. The following figure provides an example:
The happy face shown in the previous figure is a simple example of what you can achieve with manual plot positioning; using these commands, figures of frightening complexity can be built up.
The following script shows how to use gnuplot's manual positioning commands:
set multiplot unset key unset tics set polar set size 1, .5 plot [pi:2*pi] 1 lw 5 set origin 0, .5 set size .5, .5 plot 1 lw 2, .2 with filledcurves set origin .5, .5 ...