Ascending Descending
|------------------------------5-7-8-| |-8-7-5-----------------------------|
|------------------------5-6-8-------| |-------8-6-5-----------------------|
|------------------4-5-7-------------| |-------------7-5-4-----------------|
|--------------5-7-------------------| |-------------------7-5-------------|
|--------5-7-8-----------------------| |-----------------------8-7-5-------|
|-5-7-8------------------------------| |-----------------------------8-7-5-|