Setting the Box Size and Shape

The set size command allow control of the size and shape of the box. Some useful options are
set size square
Make the box square, rather than the shape of the window.

set size ratio r
(Try to) set the aspect ratio (height/width) of the box to r.

set size noratio
Restore the default aspect ratio.

set size x,y
Specify the x- and y-sizes of the box, relative to the full-screen box size. If y is omitted, then y = x is assumed.