```python
def hop_chain(hops: list) -> bool:
    """
    Determine if a list of hops forms a continuous chain.
    
    Args:
    hops: A list of tuples, where each tuple contains two elements representing the start and end of a hop.
    
    Returns:
    True if the hops form a continuous chain, False otherwise.
    """
    if not hops:
        return True
    
    # Create a set of all starting points and ending points
    starts = {hop[0] for hop in hops}
    ends = {hop[1] for hop in hops}
    
    # Check if there is exactly one starting point and one ending point
    if len(starts) != 1 or len(ends) != 1:
        return False
    
    # Get the unique starting and ending points
    start, end = starts.pop(), ends.pop()
    
    # Check if the chain is continuous by verifying that all hops start where the previous one ended
    current = start
    for hop in hops:
        if hop[0] != current:
            return False
        current = hop[1]
    
    # Check if the chain ends where it started
    return current == start
```