diff --git a/src/algorithms/aldous_broder.coffee b/src/algorithms/aldous_broder.coffee
index d4f74ca..8d83639 100644
--- a/src/algorithms/aldous_broder.coffee
+++ b/src/algorithms/aldous_broder.coffee
@@ -23,8 +23,11 @@ class Maze.Algorithms.AldousBroder extends Maze.Algorithm
     @updateAt @x, @y
     @remaining--
     @state = 1
+    @carvedOnLastStep = true
 
   runStep: ->
+    carved = false
+
     if @remaining > 0
       for dir in @rand.randomDirections()
         nx = @x + Maze.Direction.dx[dir]
@@ -37,6 +40,7 @@ class Maze.Algorithms.AldousBroder extends Maze.Algorithm
             @maze.carve x, y, dir
             @maze.carve @x, @y, Maze.Direction.opposite[dir]
             @remaining--
+            carved = true
 
             if @remaining == 0
               delete @x
@@ -47,6 +51,9 @@ class Maze.Algorithms.AldousBroder extends Maze.Algorithm
 
           break
 
+    @eventAt @x, @y if carved != @carvedOnLastStep
+    @carvedOnLastStep = carved
+
     return @remaining > 0
 
   step: ->
diff --git a/src/algorithms/backtracker.coffee b/src/algorithms/backtracker.coffee
index 765b947..799b61c 100644
--- a/src/algorithms/backtracker.coffee
+++ b/src/algorithms/backtracker.coffee
@@ -32,6 +32,7 @@ class Maze.Algorithms.RecursiveBacktracker extends Maze.Algorithm
     @updateAt x, y
     @stack.push x: x, y: y, dirs: @rand.randomDirections()
     @state = @RUN
+    @carvedOnLastStep = true
 
   runStep: ->
     loop
@@ -48,12 +49,16 @@ class Maze.Algorithms.RecursiveBacktracker extends Maze.Algorithm
 
         @maze.carve nx, ny, Maze.Direction.opposite[dir] | @STACK
         @updateAt nx, ny
+        @eventAt nx, ny unless @carvedOnLastStep
+        @carvedOnLastStep = true
         break
 
       if current.dirs.length == 0
         @maze.uncarve current.x, current.y, @STACK
         @updateAt current.x, current.y
+        @eventAt current.x, current.y if @carvedOnLastStep
         @stack.pop()
+        @carvedOnLastStep = false
         break
 
     @state = @DONE if @stack.length == 0
diff --git a/src/algorithms/binary_tree.coffee b/src/algorithms/binary_tree.coffee
index 95a5192..6cb08f7 100644
--- a/src/algorithms/binary_tree.coffee
+++ b/src/algorithms/binary_tree.coffee
@@ -39,5 +39,6 @@ class Maze.Algorithms.BinaryTree extends Maze.Algorithm
     if @x >= @maze.width
       @x = 0
       @y++
+      @eventAt @x, @y
 
     return @y < @maze.height
diff --git a/src/algorithms/eller.coffee b/src/algorithms/eller.coffee
index 8243762..f4c3996 100644
--- a/src/algorithms/eller.coffee
+++ b/src/algorithms/eller.coffee
@@ -62,6 +62,7 @@ class Maze.Algorithms.Eller extends Maze.Algorithm
         @mode = @VERTICAL
         @next_state = @state.next()
         @verticals = @computeVerticals()
+        @eventAt 0, @row
 
   computeVerticals: ->
     verts = []
@@ -88,6 +89,7 @@ class Maze.Algorithms.Eller extends Maze.Algorithm
       @state = @next_state.populate()
       @row += 1
       @initializeRow()
+      @eventAt 0, @row
 
   step: ->
     switch @mode
diff --git a/src/algorithms/houston.coffee b/src/algorithms/houston.coffee
index a79ab5d..aefa30c 100644
--- a/src/algorithms/houston.coffee
+++ b/src/algorithms/houston.coffee
@@ -38,6 +38,7 @@ class Maze.Algorithms.Houston extends Maze.Algorithm
       delete @worker.x
       delete @worker.y
       @updateAt x, y
+      @eventAt x, y
 
       # switch to wilsons and redefine the step method so it
       # no longer watches the threshold.
diff --git a/src/algorithms/hunt_and_kill.coffee b/src/algorithms/hunt_and_kill.coffee
index 6cd496a..67058b3 100644
--- a/src/algorithms/hunt_and_kill.coffee
+++ b/src/algorithms/hunt_and_kill.coffee
@@ -45,6 +45,7 @@ class Maze.Algorithms.HuntAndKill extends Maze.Algorithm
     delete @x
     delete @y
     @updateAt x, y # remove highlight from current cell
+    @eventAt x, y
     @y = 0
     @callbackRow 0 # highlight the first row
     @state = 2
@@ -75,6 +76,7 @@ class Maze.Algorithms.HuntAndKill extends Maze.Algorithm
 
           # clear highlight in row (because we set @x) and update passages at @x, @y
           @callbackRow @y
+          @eventAt nx, ny
 
           return
 
diff --git a/src/algorithms/sidewinder.coffee b/src/algorithms/sidewinder.coffee
index 4644a63..313c7a5 100644
--- a/src/algorithms/sidewinder.coffee
+++ b/src/algorithms/sidewinder.coffee
@@ -28,6 +28,7 @@ class Maze.Algorithms.Sidewinder extends Maze.Algorithm
       @maze.carve cell, @y-1, Maze.Direction.S
       @updateAt cell, @y
       @updateAt cell, @y-1
+      @eventAt @x, @y if @x - @runStart > 0
       @runStart = @x + 1
     else if @x+1 < @maze.width
       @maze.carve @x, @y, Maze.Direction.E
diff --git a/src/algorithms/wilson.coffee b/src/algorithms/wilson.coffee
index 9cc21ef..56673dd 100644
--- a/src/algorithms/wilson.coffee
+++ b/src/algorithms/wilson.coffee
@@ -36,6 +36,7 @@ class Maze.Algorithms.Wilson extends Maze.Algorithm
       @x = @rand.nextInteger(@maze.width)
       @y = @rand.nextInteger(@maze.height)
       if @maze.isBlank(@x, @y)
+        @eventAt @x, @y
         @state = 2
         @start = x: @x, y: @y
         @addVisit @x, @y
@@ -57,6 +58,7 @@ class Maze.Algorithms.Wilson extends Maze.Algorithm
           @x = @start.x
           @y = @start.y
           @state = 3
+          @eventAt @x, @y
 
         break