<!DOCTYPE html>
<style>
.block {
  width: 75px;
  height: 50px;
  z-index: -1;
  border: 5px dotted blue;
}

.container {
  border: 1px solid;
  position: relative;
  width: 100px;
  height: 100px;
  display: inline-block;
  margin-left: 50px;
  margin-bottom: 50px;
}

.abs {
  width: 50px;
  height: 50px;
  position: absolute;
  background: purple;
}
</style>
<!-- start aligned -->
<div class="container"><div class="block">
  <div class="abs"></div>
</div></div>
<div class="container"><div class="block">
 