Ascending Descending
|---------------------------4-5-| |-5-4---------------------------|
|-----------------------5-7-----| |-----7-5-----------------------|
|-----------------4-6-7---------| |---------7-6-4-----------------|
|-----------4-6-7---------------| |---------------7-6-4-----------|
|-----4-5-7---------------------| |---------------------7-5-4-----|
|-5-7---------------------------| |---------------------------7-5-|