\[2|x| + |y| = 4\]
\[Ромб\ со\ стороной\ a = \sqrt{4 + 16} = \sqrt{20} = 2\sqrt{5}.\]
\[P = 4 \cdot 2\sqrt{5} = 8\sqrt{5}.\]
\[Ответ:ромб;8\sqrt{5}.\]