diff --git a/src/main.lua b/src/main.lua
index 9cb06f5..a5e065a 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -604,7 +604,7 @@ local function VP_moveto(x,z, cx,cz,direction)
     VP_movetoy(y, 0)
     return cx,cz,direction
 end
-local function VP_optimizestack(target) -- partly deprecated for not working!
+local function VP_optimizestack(target)
     -- go from top to bottom and erase false entries until we encounter a true one.
     local index = #target
     while #target > 0 do
@@ -628,15 +628,15 @@ local function VP_createstack(buf, dimensions)
         for z=1,dimensions["z"],1 do
 
             local tempbuf = {}
-            for y=1,dimensions["y"],1 do -- for each y dimension
+            for y=1,dimensions["y"]+1,1 do -- for each y dimension
                 local placecode = buf[posasstring(x,y,z)]
                 for layer=1,3,1 do -- layers
                     table.insert(tempbuf, needstobeplaced(placecode, layer))
                 end
                 -- ceiling
-                table.insert(tempbuf, buf[posasstring(_cx,cy,_cz)] ~= 2)
+                table.insert(tempbuf, buf[posasstring(x,y,z)] ~= 2)
             end
-            --VP_optimizestack(tempbuf)
+            VP_optimizestack(tempbuf)
 
             if #tempbuf > 0 then out[posasstring(x,z)] = tempbuf end
         end