Creating a circle of alternating sizes

I'm attempting to create a scale formation that goes through an obstacle course using 14 characters and a leader. I've managed to make it work well with 3 characters and the leader, but it needs to create a circle shape with between 4 and 15 units(including the leader).

  GameObject[] birds =  GameObject.FindGameObjectsWithTag("EditorOnly");
     int birdcount = 1;
     int birdnumber = 1;
     foreach(GameObject bird in birds){
         birdnumber++;
     }
     float radius = birdnumber*.5f;
     foreach(GameObject bird in birds){
         birdcount++;
         Vector3 b = new Vector3(0,0,0);
         if(cubeNumber == 4){
             b = new Vector3(rigidbody.position.x-(.5f*birdcount)-bird.rigidbody.position.x, 0, rigidbody.position.z-bird.rigidbody.position.z);

         }else{
             //b = new Vector3((rigidbody.position.x+(.75f*birdnumber))- bird.rigidbody.position.x, 0, rigidbody.position.z- bird.rigidbody.position.z);


             if(birdcount == 2){
                 b = new Vector3((rigidbody.position.x+(.75f*birdcount))- bird.rigidbody.position.x, 0, rigidbody.position.z- bird.rigidbody.position.z);
             }else if(birdcount == 3){
                 b = new Vector3((rigidbody.position.x+(.375f*birdcount))- bird.rigidbody.position.x, 0, (rigidbody.position.z-(.375f*birdcount))- bird.rigidbody.position.z);
             }else if(birdcount == 4){
                 b = new Vector3((rigidbody.position.x+(.375f*birdcount))- bird.rigidbody.position.x, 0, (rigidbody.position.z+(.375f*birdcount))- bird.rigidbody.position.z);
             }
         
             if(birdcount == 5){
                 b = new Vector3((rigidbody.position.x+(.75f*birdcount))- bird.rigidbody.position.x, 0, rigidbody.position.z- bird.rigidbody.position.z);
             }else if(birdcount == 6){
                 b = new Vector3((rigidbody.position.x+(.375f*birdcount))- bird.rigidbody.position.x, 0, (rigidbody.position.z-(.375f*birdcount))- bird.rigidbody.position.z);
             }else if(birdcount == 7){
                 b = new Vector3((rigidbody.position.x+(.375f*birdcount))- bird.rigidbody.position.x, 0, (rigidbody.position.z+(.375f*birdcount))- bird.rigidbody.position.z);
             }

         }
         bird.rigidbody.velocity = b;
     }