Does the snake method only work on circular grills?
The point of the snake method is to provide constant, indirect, heat and smoke for a extended period of time.

The burning charcoal lights just the next bit of fuel in the chain instead of the entire mass of fuel that would be consumed in a normal charcoal arrangement. By having only a little of the fuel and smoking wood burn at a time it makes the fuel last longer and keeps the smoke level low.

This method will work for any shape of grill/smoker. Depending on how big your grill is you may have to have more fuel in your snake to keep it at temperature. Depending on where you weave your snake you may have to move your meat around to keep it away from the direct heat.