from typing import List


def is_tree(pattern: List[str], row: int, col: int) -> bool:
    """Checks if the input pattern has a tree at the input coordinates."""
    width = len(pattern[0])    
    pat_col = col-col//(width-1)*(width-1)  # Turn width into an index

    if pattern[row][pat_col] == "#":
        return True
    return False