Here are four different exercises you can carry out just using four poles (red) laid out in a cross.
1️⃣ Top left, with the pattern drawn in brown. Most suitable for walk and trot, this exercise gets the rider thinking about accuracy and coordination through turns and on straight lines. The circular shapes encourage the horse to have an inside bend, and promote suppleness, whilst the straight lines encourage balance and straightness. The poles can be raised to help build the horses muscles and to make the exercise slightly more challenging.
2️⃣ Top right, pink circles. A nice, easy exercise which can be ridden, lunged and long reined in walk, trot and canter. While promoting inside bend, suppleness and balance, this exercise is good for focusing on tempo and rhythm of the paces, and is especially useful in canter. You can also use the poles as markers in walk and trot and leg yield from the middle of one pole, to the middle of the next, and then to the outside of the next pole.
3️⃣ Bottom left, more circles! Drawn in blue, you ride four small circles within one big circle, using the end of each pole as a marker to keep the circles all at a similar size. This is a great exercise to ride in trot, and is a great exercise if your horse struggles with inside bend.
4️⃣ Bottom right in green, alternate poles. This is a great exercise to canter over. It will help to promote balance and regularity of the tempo. If required, you could have on pair of poles on the floor to, and the other pair of poles raised to really give the horse a workout through those all important hind quarter muscles!