`paddings = [[0, 0], [0, 0]]`:

```
x = [[[[1], [2]], [[3], [4]]]]
```

The output tensor has shape `[4, 1, 1, 1]` and value:

```
[[[[1]]], [[[2]]], [[[3]]], [[[4]]]]
```

(2) For the following input of shape `[1, 2, 2, 3]`, `block_shape = [2, 2]`, and
    `paddings = [[0, 0], [0, 0]]`:

```
x = [[[[1, 2, 3], [4, 5, 6]],