flex アイテム折り返しなし　flex-wrap: nowrap;

row

A
B
C

row-reverse

A
B
C

column

A
B
C

column-reverse

A
B
C

flex アイテムの折り返し　flex-wrap: wrap;

row

A
B
C

row-reverse

A
B
C

column

A
B
C

column-reverse

A
B
C

逆方向に折り返し　flex-wrap: wrap-reverse;

row

A
B
C

row-reverse

A
B
C

column

A
B
C

column-reverse

A
B
C