-This BD style magic wall converts rocks into diamonds and vice versa. Note that
-a magic wall can only be activated for some limited time. It can also turn mega
-rocks into nitro packs, nitro packs into mega rocks. Even flying diamonds and
-rocks pass them to be converted into each other, but they do that from bottom to
-up, of course.
+This is a BD style magic wall. It gets activated for a limited duration by
+rocks or gems that fall on it. While activated, they can fall through it, and
+rocks turn into BD style diamonds, and gems turn into BD style rocks.
+After the magic wall has stopped running, it cannot be activated again.
The duration in seconds for which magic walls are active is configurable.
A duration of zero will let the wall run forever.