python - How to combine successive rows with an increasing overlap between them (just like a rolling window)?

Question

I am currently starting to learn Pandas and struggling to do a task with it. What I am trying to do is to augment the data stored in a dataframe by combining two succesive rows with an increasing overlap between them. Just like a rolling window.

I believe the question can exemplified with this small dataframe:

df = pd.DataFrame([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]], columns=['A', 'B', 'C', 'D'])

which gives:

    A   B   C   D
0   1   2   3   4
1   5   6   7   8
2   9   10  11  12

With it, what I want to accomplish but I don't know how to, is a dataframe like the next one:

    A   B   C   D
0   1   2   3   4
1   2   3   4   5
2   3   4   5   6
3   4   5   6   7
4   5   6   7   8
5   6   7   8   9
6   7   8   9   10
7   8   9   10  11
8   9   10  11  12

As if we were using multiple rolling windows between each pair of the initial dataframe. Note that I am not using this specific dataframe (the values are not really ordered like 1,2,3,4...). What I am using is a general dataframe imported from a csv.

Is this possible?, thanks in advance!

---

Edit

Thanks to all the responses. Both answers given by anky and Shubham Sharma work perfect. Here are the results obtained by using both of them with my real dataframe:

Initial dataframe

After adding multiple rolling windows as my question needed

Answer 1

May be not as elegant, but try:

def fun(dataframe,n):
    l = dataframe.stack().tolist()
    return (pd.DataFrame([l[e:e+n] for e,i in enumerate(l)],
        columns=dataframe.columns).dropna().astype(dataframe.dtypes))

---

fun(df,df.shape[1])

   A   B   C   D
0  1   2   3   4
1  2   3   4   5
2  3   4   5   6
3  4   5   6   7
4  5   6   7   8
5  6   7   8   9
6  7   8   9  10
7  8   9  10  11
8  9  10  11  12