.box .boxB1{background:url(../../img/box_corner_top_l.gif) left top no-repeat;}
.box .boxB2{background:url(../../img/box_corner_top_r.gif) right top no-repeat;}
.box .boxB3{background:url(../../img/box_corner_bot_l.gif) left bottom no-repeat;}
.box .boxB4{background:url(../../img/box_corner_bot_r.gif) right bottom no-repeat;}