Применение маски к box-shadow

.wrapper {
  width: 200px;
  height: 200px;
  filter:drop-shadow(17px 13px 7px rgba(0,0,0,0.75));
}
.b {
  width: 200px;
  height: 200px;
  background-color: yellow;
  border: 2px solid black;

  
  -webkit-mask: radial-gradient(
    circle at center top,
    transparent 30px,
    black 31px
  ) top / 100% 51%, 
  radial-gradient(
    circle at right bottom,
    transparent 30px,
    black 31px
  ) right bottom / 51% 51%, 
  radial-gradient(
    circle at left bottom,
    transparent 30px,
    black 31px
  ) left bottom / 51% 51%;
  
  -webkit-mask-repeat: no-repeat;
}

<div class="wrapper">
  <div class="b"></div>
</div>