2 is in triple threat position
(i) 1, 3 & 4 all are v-cutting
(ii)2 pass to 4
(iii)2 cut to basket
(iii)1 down screen for 3
(iv) 4 pass to any player for shot
rebound & rotate clockwise
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.