This is an excellent drill to learn and practice proper court coverage when playing from the baseline.
According to where the player hits the ball to (down-the-line or cross-court), there is a recovery spot that the player should get back to in order to be in the middle of the possible angles that the opponents might use.
Therefore there are two cones: one orange and one yellow that are placed just inside the baseline, same side with the player:

- the orange cone should be the recovery spot for the down-the-line shots,
- the yellow cone is the recovery spot when sending the ball cross-court;
Notice that when the player hits the ball cross-court, there is less court to recover to (yellow cone) thus spending less energy compared to the down-the-line shot which has a larger way to recover to (orange cone).

The ball machine will send the balls deep to my right side (forehand) and according to where I hit the ball to (first cross-court, then down-the-line), I will recover behind the respective spot: behind the yellow cone for cross-court shots, behind the orange cone for down-the-line shots.
Footwork wise, whenever you feel rushed and you have more court to cover, you should use a cross-over, followed by side-shuffle steps.

Secret: When off-balance, or stretched out wide, hit most of your shots cross-court - the ball travels longer (giving you more time to get back in play), and you'll have less court to cover your opponent's possible angles.