body {
  font-size: 12px;
}

.wrapper {
  display: flex;
  flex-direction: row;
  width: 400px;
  height: 400px;
  background: #ccc;
}

.box {
  width: 100px;
  height: 100px;
  overflow: hidden;
  border: 1px solid black;
  margin: 10px;
}

.red {
  color: white;
  background: red;
}

.blue {
  color: white;
  background: blue;
}

.green {
  color: white;
  background: green;
}