Changes

# the Activity-stop Button

# the Activity-stop Button

=== Programming challenge ===

=== Programming challenges ===

Could you modify Reflections so that it supports rotational symmetry as well as reflective symmetry?

* Could you modify Reflections so that it supports rotational symmetry?

* Could you modify Reflections so that it supports glide symmetry?

=== Where to get Reflection ===

=== Where to get Reflection ===