<div class="first">
  <div class="child-of-first">child of first</div>
</div>
<div class="second"></div>

body {
  background: #282828;
}
.first,
.second {
  position: relative;
  width: 150px;
  height: 150px;
  background: red;
  z-index: 1;
}
.second {
  background: blue;
  margin-top: -75px;
  margin-left: 75px;
  z-index: 2;
}
.child-of-first {
  position: absolute;
  top: 80px;
  left: 30px;
  background: #ffffff;
  z-index: 3;
}