def addLists(list1, list2):
    """Add lists together by value. i.e. addLists([1,1], [2,2]) == [3,3]."""
    # Find big list and small list
    blist, slist = list(list2), list(list1)
    if len(list1) > len(list2):
        blist, slist = slist, blist

    # Overlay small list onto big list
    for i, b in enumerate(slist):
        blist[i] += b

    return blist