MARKER:  O = lua:item_pickup_change_flags { \
             level_flags="!no_tele_control", item="icy rune of Zot" \
         }

MARKER:  O = lua:item_pickup_change_flags { \
             level_flags="!no_tele_control", item="icy rune of Zot" \
         }

MARKER:   A = feat:<feature_name> or timer:

MARKER:   A = feat:<feature_name> or lua:<marker_expr>

          Timer feature markers set a timer on a particular square;
          when time runs out, the feature at that square is changed
          (usually to floor). For instance:

          Lua markers are used for more complex triggers, such as for
          bazaar and labyrinth gates, rune pickup triggers for
          the branches of Hell, fog generators, etc.

          MARKER: A = timer: 500-1000

          Here's a Lua marker that creates a cloud generator:

          Sets a timer that's between 500-1000 turns, inclusive, at the
          end of which whatever feature is on A gets converted to floor.
          You can specify the final feature with a feat: qualifier:
          MARKER: A = timer: 500 feat:deep_water
          This sets a timer for exactly 500 turns, and changes the
          feature to deep water at the end of it.
          Another type of MARKER sets generators of various clouds, e.g.:

          An important thing to note with markers is that they are
          also considered map transforms along with SUBST, NSUBST and
          SHUFFLE. You usually want to place a MARKER line after all
          SUBST, NSUBST and SHUFFLE lines so that the final position
          of the marker key is used. For instance, if you want to
          attach a marker to the rune in a map when you're randomising
          the position of the rune, this is a mistake:
          MARKER: O = lua:<expr>
          SHUFFLE: Oa/|c
          because the marker will be placed at O (the rune), then O
          may be shuffled to a different position. The correct order
          in this case is:

          SHUFFLE: Oa/|c
          MARKER: O = lua:<expr>