Purpose - to practice proper defensive stance / slide
1 - Start at cone A - defensive shuffle all the way to the middle cone / touch / then defensive slide back to A
2 - Shuffle to the right to the next cone / touch / shuffle to the middle cone / touch / then back to cone and repeat until player reaches back to A
Good team defence is five players guarding the ball, not five separate one-on-ones. The shell drill is where that starts, so here is how to teach help-side positioning and rotations from the first week of the season.
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.