This game takes advantage of a simple pattern. The basic setup involves you sitting on the ground with two treat dishes on both sides of your knees. There is a cone in front of you. The initial objective is to shape your dog to go around that cone from one side to the other. As they round the cone and approach the treat bowl on that side, place a cookie into it. The dog should eat the cookie as soon as they arrive and smoothly turn around to go around the cone to your other side, where they will collect a cookie from that bowl.
Thus you end up with a basic pattern - the dog goes from one treat bowl to the other by going around the cone in front of you. As the dog is successful, increase the amount of space between you and the cone. Now the dog must actively move away from you, interact with the obstacle, and return to your other side to collect their reward.
This is a shaping game, so the amount of handler help should be minimal - if your dog is struggling, changing your setup (I.e. moving the cone closer) is preferable. There is no verbal marker in this game, and the distance your hand travels to place the next cookie in the right bowl should be minimal.
The most common issue that comes up is cutting across the middle line instead of going around the cone, for example going around from left to right and cutting across from right to left. If this is not rewarded, the dog tends to then go around the cone from the side that they are now on (from left to right in our example). That gets rewarded, and many times that's all you needed to get the dog back on track.
Some dogs, however, try to continue the new pattern - cut across the middle in one direction and go around the cone in the other for their one cookie. This is not a pattern you want developing - it is crucial that the dog alternates direction with every rep. You can wait them out until they offer going around the cone in the direction they keep trying to skip, or you can make the set up easier and move the cone closer to you (half the distance).
If your dog lies down, or otherwise offers a stationary behavior, throw a reset cookie towards the line they should be traveling - when they get there and see the cone, they are likely to remember what they were doing and offer going around it again.
This is a fairly mentally intensive game, so watch your session lengths. Some dogs thrive on patterns and will go around that cone a hundred times. Other dogs will start to make deliberate mistakes when asked to do the same thing too many times in a row - ending the session or doing a different drill is better there to avoid building frustration.
Once the dog understands the pattern and that they are not to cut across the middle line between you and the obstacle, you can increase the complexity of the thing they are doing in the middle. The simplest progression involves putting a jump right behind the cone - such that you are perpendicular to it. The dog then goes out, jumps a tight wrap before coming back to your other side to collect their treat. Since they are going back and forth, they are working both directions evenly.
From here your options open up. Two jumps on either side of the cone - progress to moving them further apart as the dog is successful to make two separate lines with a turn at the end. Add a tunnel to the picture - the dog will now take one jump, continue on their line to take the curved tunnel, come out from the other side to take that jump before coming back to you.
Expand that further - set up a jump grid, an element that allows your dog to turn (tunnel or cone or jump), then another jump grid on the other side. Set up weaves - or even just a single 2x2 to practice the entry. Making use of this pattern allows you to maximize the efficiency of your training.
By taking handler motion and start line stays out of the picture and using the pattern to give your dog confidence in where to go next, you allow them to concentrate on their job of obstacle execution. By applying the pattern to longer chains of obstacles, you let your dog develop confidence in working at a distance from you. The one-obstacle variants are great for a small space, while the space-requiring grids and sequences give your dog a workout with minimal effort on your part. The back and forth nature of the pattern equalizes the number of reps done with turning in each direction, keeping your dog's muscle development balanced.
Naturally, this game must be balanced out by other drills and games that practice handler focus and prioritize speed. Unless you have a dog who naturally likes moving quickly, their speed of execution in this game is likely to be leisurely - especially in the initial stages of learning the pattern and how it applies to variations. This is a game to add to your arsenal of tools to keep your agility partner balanced between obstacle and handler focus.