JSFiddle: https://jsfiddle.net/UnsungHero97/80qod7aL/5/

HTML

<div class="box_shadow"></div>

CSS

.box_shadow {
  width: 100px;
  height: 100px;
  margin: 100px;
  box-shadow:
    -52px -52px 0px 0px #f65314,
    52px -52px 0px 0px #7cbb00,
    -52px 52px 0px 0px #00a1f1,
    52px 52px 0px 0px #ffbb00;
}

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/d96567ae-b371-4519-8883-385d4a73c35b/Untitled.png