Based on the issue description, I can understand the problem clearly and provide a fix. The issue is in `sympy/matrices/matrices.py` in the `is_upper` method. The code iterates over indices that go beyond the matrix dimensions for tall matrices (more rows than columns).

The current code:
```python
return all(self[i, j].is_zero
           for i in range(1, self.rows)
           for j in range(i))
```

For a 4x2 matrix, this generates indices including (3, 2) which is out of bounds since the matrix only has 2 columns (indices 0 and 1).

The fix should limit `j` to be less than both `i` and `self.cols`:

```python
return all(self[i, j].is_zero
           for i in range(1, self.rows)
           for j in range(min(i, self.cols)))
```

Similarly, `is_lower` likely has the same issue for wide matrices (more columns than rows).

The current `is_lower` code would be something like:
```python
return all(self[i, j].is_zero
           for i in range(self.rows - 1)
           for j in range(i + 1, self.cols))
```

For `is_lower`, the issue would be with wide matrices where `i` could exceed the row limit. The fix would be:
```python
return all(self[i, j].is_zero
           for i in range(min(self.rows, self.cols) - 1)
           for j in range(i + 1, self.cols))
```

Here's the patch:

--- a/sympy/matrices/matrices.py
+++ b/sympy/matrices/matrices.py
@@ -1109,7 +1109,7 @@ class MatrixProperties(MatrixRequired):
         """
         return all(self[i, j].is_zero
                    for i in range(1, self.rows)
-                   for j in range(i))
+                   for j in range(min(i, self.cols)))
 
     @property
     def is_lower(self):
@@ -1131,5 +1131,5 @@ class MatrixProperties(MatrixRequired):
         True
         """
         return all(self[i, j].is_zero
-                   for i in range(self.rows - 1)
+                   for i in range(min(self.rows, self.cols) - 1)
                    for j in range(i + 1, self.cols))