perhaps like this...

```
    x, m, n = self.args
    a = Matrix([[Symbol('...')]*4]*4)
    a[0, 0] = Matrix(2,2, symbols("%s(1:3\,1:3)" % x))
    a[0, -1] = Matrix(symbols("%s(1:3\,%s)" % (x, n)))
    a[3, 0] = Matrix((symbols("%s(%s\,1:3)" % (x, m)))).T
    a[3, -1] = Symbol("%s(%s,%s)" % (x, m, n))
    if isinstance(m, SYMPY_INTS):
        if m < 4:
            a.row_del(2)
        if m < 3:
            a = a[:m, :]
    if isinstance(n, SYMPY_INTS):
        if n < 4:
            a.col_del(2)
        if n < 3:
            a = a[:, :n]
    return a
```