<div style="position:relative; background-color:#fff; margin:20px 30px; padding:40px 10px 20px 10px; box-shadow:0 0 3px rgba(0,0,0,.3);">左上と右下にマステが貼られた紙に書く文章<div style="position:absolute; top:0; left:-30px; display:block; transform:rotate(-15deg); -webkit-transform:rotate(-15deg); border-left:dotted 2px rgba(0,0,0,.2); border-right:dotted 2px rgba(0,0,0,.2); box-shadow: 0 0 3px rgba(0,0,0,.3); background-color:rgba(255,250,100,.5); width:210px; height:30px;"></div><div style="position:absolute; bottom:10px; right:-40px; display:block; transform:rotate(-45deg); -webkit-transform:rotate(-45deg); border-left:dotted 2px rgba(0,0,0,.2); border-right:dotted 2px rgba(0,0,0,.2); box-shadow: 0 0 3px rgba(0,0,0,.3); background-color:rgba(255,250,100,.5); width:120px; height:30px;"></div></div>