Flexbox

flex-direction: row (default)

CSS
.container {
  display: flex;
  flex-direction: row
}
Box-1
Box-2
Box-3
Box-4
Box-5
Box-6
Box-7
Box-8
Box-9

flex-direction: column

CSS
.container {
  display: flex;
  flex-direction: column
}
Box-1
Box-2
Box-3
Box-4
Box-5
Box-6
Box-7
Box-8
Box-9

flex-direction: row-reverse

CSS
.container {
  display: flex;
  flex-direction: row-reverse
}
Box-1
Box-2
Box-3
Box-4
Box-5
Box-6
Box-7
Box-8
Box-9

flex-direction: column-reverse

CSS
.container {
  display: flex;
  flex-direction: column-reverse
}
Box-1
Box-2
Box-3
Box-4
Box-5
Box-6
Box-7
Box-8
Box-9