Universal Texture of Quark and Lepton Mass Matrices with an Extended Flavor $2\leftrightarrow 3$ Symmetry

Stimulated by a quark mass matrix texture which has recently been proposed by Matsuda and Nishiura, a universal texture of quark and lepton mass matrices is proposed, where an extended flavor $2\leftrightarrow 3$ symmetry is assumed. And, thereby, the neutrino masses and mixings are speculated.