Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to build a dog agility course [title] Create some obstacles. [step] These are important for increasing your dog's agility and running skills. [title] Make weaves (a type of obstacle dogs weave through).

Ending1: [step] You can make those from pvc pipes as well but they are more time consuming. [substeps] The best way to do this is to buy very large, tall orange cones, line them up in a line and have your dog weave through. Ending2: [title] Build a bridge if it is a simple obstacle course. [title] Build a new field of seeds if this is an obstacle course. Ending3: [step] Make them part of your training course. [title] Consider creating a class or two for your dog because you will want the academy to know you are training. Ending4: [step] Also remember that the energy generated by weaving and running around obstacles can send them flying. This step is necessary if you want to move your dog for mobility.

Answer format: ending1/ending2/ending3/ending4