CLSD LN allows you to select a set of line entities whose
projections define a closed region in the current view.

Choose a Selection Menu option to specify the desired set
of line entities.

Selected lines that do not form a closed shape are rejected
and you are prompted to press <Enter> to continue. Choose
from a Selection Menu option again to reselect desired
entities.

Locate the polar reference axis.

The polar moment of inertia is displayed for the polygon
formed by the projected lines.

You can press <Enter> to indicate a new reference axis.
