Answer:
The square has 4-fold reflectional symmetry. The regular octagon has 8-fold symmetry.
Explanation:
For a square,
There are two lines of symmetry along two diagonals and
two lines of symmetry along midpoints of two pairs of opposite sides.
Therefore, there are 4 lines of reflectional symmetry in total.
For a regular octagon,
There are four lines of symmetry along four diagonals and
four lines of symmetry along midpoints of four pairs of opposite sides.
Therefore, there are 8 lines of reflectional symmetry in total.