```python
from typing import List

def tide_marks(levels: List[int]) -> List[int]:
    if not levels or len(levels) < 3:
        return []

    peak_positions = []
    for i in range(1, len(levels) - 1):
        if levels[i] > levels[i - 1] and levels[i] > levels[i + 1]:
            peak_positions.append(i)

    return peak_positions
```