The function takes a string as the input and converts it into a sequence of numerical words.

[CODE]:
```python
def convert_to_numerical_words(input_string):
    numerical_words = []

    # Convert each character in the string to its corresponding numerical word
    for char in input_string:
        if char == 'H':
            numerical_words.append("zero")
        elif char == 'e':
            numerical_words.append("one")
        elif char == 'l':
            numerical_words.append("two")
        elif char == 'o':
            numerical_words.append("four")

    return numerical_words
```

This code snippet approximates the behavior of the function by mapping each character in the input string to its corresponding numerical word. It outputs a list of these numerical words.

You can try running this code with different input strings to see if it accurately represents the behavior of the given function.