   unless @_should_debug me
     yield return
   #.........................................................................................................
-  yield texr 'µ17', "\\begin{scope}[on background layer]"
+  yield texr 'ð22', "\\begin{scope}[on background layer]"
   #.........................................................................................................
   ### TAINT use fixed size like 1mm ###
   top       = ( @_top_from_rownr     me, 1             ) - 3
   bottom    = ( @_bottom_from_rownr  me, me.grid.height ) + 3
   for colnr in [ 1 .. me.grid.width + 1 ]
     x = @_left_from_colnr me, colnr
-    yield texr 'µ18', "\\draw[sDebugCellgrid] (#{x},#{top}) -- (#{x},#{bottom});"
+    yield texr 'ð23', "\\draw[sDebugCellgrid] (#{x},#{top}) -- (#{x},#{bottom});"
   #.........................................................................................................
   ### TAINT use fixed size like 1mm ###
   left      = ( @_left_from_colnr    me, 1             ) - 3
   right     = ( @_right_from_colnr   me, me.grid.width  ) + 3
   for rownr in [ 1 .. me.grid.height + 1 ]
     y = @_top_from_rownr me, rownr
-    yield texr 'µ19', "\\draw[sDebugCellgrid] (#{left},#{y}) -- (#{right},#{y});"
-  #.........................................................................................................
-  yield texr 'µ20', "\\end{scope}"
+    yield texr 'ð24', "\\draw[sDebugCellgrid] (#{left},#{y}) -- (#{right},#{y});"
+  #.........................................................................................................
+  yield texr 'ð25', "\\end{scope}"
   #.........................................................................................................
   yield return
 

  unless @_should_debug me
    yield return
  #.........................................................................................................
  yield texr 'µ21', "\\begin{scope}[on background layer]"
  #.........................................................................................................
  for designation, d of me.field_dimensions
    ### TAINT use fixed size like 1mm ###

  p             = if direction is 'width' then 'colnr' else 'rownr'
  #.........................................................................................................
  ### TAINT should implement this in intergrid ###
  for cell from IG.GRID.walk_cells_from_selector me.grid, selector
    lanenr = cell[ p ]
    continue if seen_lanenrs.has lanenr
