<div class="box">
  <p>高さ:100px</p>
  <div class="example ex01"></div>
</div>

<div class="box">
  <p>高さ:50px</p>
  <div class="example ex02"></div>
</div>

<div class="box">
  <p>高さ:0</p>
  <div class="example ex03"></div>
</div>

* {
  box-sizing: border-box;
}
body {
  min-height: 100vh;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}
.box {
  text-align: center;
}
.box:not(:last-of-type) {
  margin-right: 5%;
}
.example {
  width: 100px;
  border-bottom: 20px solid #a0e2c2;
  border-left: 20px solid #e2a0b4;
  border-right: 20px solid #eec496;
}
.example.ex01 {
  height: 100px;
}
.example.ex02 {
  height: 50px;
}
.example.ex03 {
  height: 0;
}