This drill is a modified Round the Horn drill with play starting at 3rd base.

Setup with two first basemen, two second basemen, one catcher, and one third baseman. Notice the alignment of the backup players at 2nd and 1st base.

Extra players waiting to join the rotation line up on the grass, behind 3rd base. These players must remain alert, since the coach will be hitting balls to the third baseman to start the drill.

The coach hits ball while standing at home plate.

Key:
The third baseman will field three balls hit by the coach before all players rotate to their next position.

The drill starts with the coach hitting a ground ball straight at the third baseman.

The third baseman fields the ball and throws to second.

The second baseman turns a double-play, throwing to first base.

The first baseman throws the ball to the catcher, who simulates a tag at home.

When the ball reaches home, the coach hits another grounder to the same third baseman, this time making him range to his left.

The third baseman fields the ball and throws to 2nd base to begin the double-play, again.

When the ball reaches home plate, the coach hits (or throws) a high pop-up to the same third baseman.

The third baseman fields the pop-fly and throws home to the catcher, who simulates a tag at the plate.

The first round of the drill is now complete and all players rotate to their next positions:

3rd baseman goes to 2nd-base backup
2nd base backup moves up to 2nd base
2nd baseman goes to 1st base backup
1st base backup moves up to 1st base
1st baseman goes to catcher's position
catcher goes to end of line behind 3rd base
1st player in line behind 3rd base becomes the third baseman.

In this illustration, the position tags remained the same to show where the players ended-up after they completed their rotation.

Once the rotation is complete, the coach hits a grounder to the 3rd baseman and the drill starts all over again.