Simplify the following text for a Grade 4 native English-speaking person.
Original: The north side of the perimeter wall is still standing ; the distinctive triangular brick wedges at each end are modern additions , having been constructed in the early 19th century to shore up the wall .
Simplified: The north side of the outside wall is still standing . It has triangular brick wedges at each end , added in the early 1800 's to hold up the wall .