//shapes to be spawned
public List<GameObject> shapes;
//shapes that are in game
public List<GameObject> spawnedShape;
//num of next shape to be places
public int next;
//list of shapes that can be spawned
public List<int> shapeCount;
System.Random random;


void Start()
{
    random = new System.Random();
    for (int i = 0; i < 4; i++)
    {
        //adds shapes that can be added into shapecount list.
        for(int j = 0; j < 4; j++)
        {
            shapeCount.Add(i);
        }
        //load game objects from resources into list
        GameObject go = Resources.Load("shape" + i) as GameObject;
        shapes.Add(go);
    }
    //set next shape
    int next = setNext();
}

void Update()
{
    if (Input.GetButton("Fire1")) {
        spawnShape();
    }
}

public int setNext()
{
    if (shapeCount.Count != 0)
    {
        int num = random.Next(0, shapeCount.Count);
        return shapeCount[num];
    }
    else return -1;
}

void spawnShape()
{
    if(next == -1)
    {
        Debug.Log("Out of shapes");
    }else
    {
        //creates instance of shape
        GameObject go = Instantiate(shapes[next]);
        //creates and assigns random x, y coordinate
        int x = random.Next(0, 500);
        int y = random.Next(0, 500);
        go.transform.position = new Vector3(x, y, 0);
        spawnedShape.Add(go);
    }
    //gets colour of next shape
    next = setNext();
}