index.html

<div></div>

style.css

div {
  width: 100px;
  height: 100px;
  border: 1px solid red;
  outline: 1px solid red;
  outline-offset: 5px;
  margin: 100px;
  position: relative;
  -webkit-transform: rotate(45deg);
  transform: rotate(45deg);
}

div:before {
  content:"";
  width: 130px;
  height: 200px;
  display:block;
  background: #fff;
  transform:translate(-10px,-25px) rotate(45deg);
}

waqHs.markdown

waqHs

A Pen by Airen on CodePen.

License.