Suppose I have dispose of two list For the following lists (or any other)

```
U=[100, 200, 300]
V=[40, 50, 60]
A=[[1,2,3],[4, 5, 6],[7, 8, 9]]
```

How to append U, V, U and V to A in such a way that the final result be `B = [[1,2,3],[4, 5, 6],[7, 8, 9],[100, 200, 300]]`

or `B = [[1,2,3,100],[4, 5, 6,200],[7, 8, 9,300]]`

or `c = [[1,2,3,100],[4, 5, 6,200],[7, 8, 9,300], [40, 50, 60, a]]`

.

for `a`

given. I have the same question with matrix and vectors. And is there a mechanism to go back to list from matrix and vectors ?