mock.json

{
   "steps": [
      {
         "step": [
            {
               "agent": {
                  "color": -1,
                  "id": 8,
                  "position": [
                     -300.0,
                     0.0
                  ],
                  "type": 1,
                  "velocity": 7
               }
            },
            {
               "agent": {
                  "color": -1,
                  "id": 9,
                  "position": [
                     -300.0,
                     0.0
                  ],
                  "type": 1,
                  "velocity": 7
               }
            }
         ]
      },
      {
         "step": [
            {
               "agent": {
                  "color": 99,
                  "id": 8,
                  "position": [
                     -300.0,
                     0.0
                  ],
                  "type": 1,
                  "velocity": 7
               }
            },
            {
               "agent": {
                  "color": 100,
                  "id": 9,
                  "position": [
                     -300.0,
                     0.0
                  ],
                  "type": 1,
                  "velocity": 7
               }
            }
         ]
      }
   ]
}