Picture 1: O1 & O2 dribble full speed to the half court line and place the ball on the floor. At the same time, X1 & X2 sprint to the half way line, where they pick the stationary ball up from the floor.
Picture 2: X1 takes the ball and tries to score at the basket from where they came, whilst O1 plays defense against them. X2 takes the ball and tries to score at the basket from where they came, whilst O2 plays defense against them. Play to a score. At the end ball is passed to the same line from where it came, players join opposite lines on the same baseline, and drill is repeated.

1-1 fundamentals in a half or quarter court setting.

Force the offensive player to stay on the same side of the floor. Penalise the defense when offense score, or when offense get an offensive rebound. Reward the defense when they get a stop, or when they take a charge.

Make sure both ends start at the same time every rotation. With older players ensure that similar position players are matched up.