private void OnMouseUp()
    {
        Collider2D[]    results = new Collider2D[1];
        ContactFilter2D filter  = new ContactFilter2D();

        filter.SetLayerMask(houseLayer);
        coll.OverlapCollider(filter, results);
        if (results[0] != null && results[0].GetComponent <House>())
        {
            House h = results[0].GetComponent <House>();
            if (h.AtCapacity())
            {
                transform.position = start;
            }
            else
            {
                h.AddPerson(this);
            }
        }
    }