diff --git a/init.lua b/init.lua
index 10bdc2c..a42d53f 100644
--- a/init.lua
+++ b/init.lua
@@ -1,4 +1,3 @@
-local statedir = minetest.get_worldpath() .. '/' .. minetest.get_current_modname() .. "/"
 local oldprint=print
 local function print(...)
  for k,v in ipairs({...}) do
@@ -6,56 +5,76 @@ local function print(...)
  end
 end
 print("Test3D loading.")
+
+local tInstructions = {
+"NOP",
+"ADD",
+"SUB",
+}
+--[[
+local statedir = minetest.get_worldpath() .. '/' .. minetest.get_current_modname() .. "/"
 print("State directory: "..statedir)
 if not digiline then
  print("Digilines not found.")
  return
+end
+]]--
+local function push(pos,val)
+ local meta = minetest.get_meta(pos)
+ local sstack = ""
+ local stack = string.split(meta:get_string("stack"),"\n")
+ if #stack > 15 then
+  print("Stack overflow at "..pos.x..","..pos.y..","..pos.z)
+  table.remove(stack,1)
  end
+ stack[#sstack+1] = tostring(val)
+ for k,v in ipairs(stack) do
+  sstack = sstack .. v .. "\n"
+ end
+end
+local function pop(pos)
+ local meta = minetest.get_meta(pos)
+ local sstack = ""
+ local stack = string.split(meta:get_string("stack"),"\n")
+ local n = table.remove(stack,#stack) or 0
+ stack[#sstack+1] = tostring(val)
+ for k,v in ipairs(stack) do
+  sstack = sstack .. v .. "\n"
+ end
+ return tonumber(n)
+end
 local function t21_digiline_receive(pos, node, channel, msg)
  print(pos,node,channel,msg)
+ meta = minetest.get_meta(pos)
+ if meta:get_string("state") == "waiting" and meta:get_string("waitingfor") == channel then
+  push(pos,msg)
+ end
 end
 print("Created T21 digiline function")
 
-print("Loading/creating states")
-_G.test3d = {}
-_G.test3d.states={}
--- states:
---[[
-{
-mem = {4096 ints}
-nodes = int
-pc = int
-}
-]]--
-function _G.test3d.save()
- local f = io.open(statedir.."/states.txt","wb")
- for k,v in pairs(test3d.states) do
-  f:write(tostring(k).."\n")
-  local g=io.open(statedir.."/"..tostring(k))
-  for l,m in ipairs(test3d.states[k]) do
-   g:write(tostring(m).."\n")
-  end
-  g:close()
- end
- f:close()
+local function t21_set_infotext(pos)
+ local meta=minetest.get_meta(pos)
+ local running="false"
+ if meta:get_int("test3d_running") == 1 then running="true" end
+ meta:set_string("infotext","Running: "..running.."\nState: "..meta:get_string("state").."\nPC: "..tostring(meta:get_int("pc")).."\nACC: "..tostring(meta:get_int("acc")).."\nBAK: "..tostring(meta:get_int("bak")))
 end
-_G.test3d.laststate=0
-_G.test3d.genstate = {}
-local statetab={}
-os.execute("mkdir "..statedir) -- just in case, 50/50 this kills minetest on some platforms
-local f=io.open(statedir.."/states.txt","rb")
-local statetab={}
-if f ~= nil then
- f:close()
- for l in io.lines(statedir.."/states.txt") do
-  print("State: "..l)
- end
-end
-print("Creating T21 formspec")
+
 local function t21_set_meta(pos)
- minetest.get_meta(pos):set_string("formspec", "field[channel;Channel;${channel}]\nfield[statename;State;${statename}]")
+ local meta = minetest.get_meta(pos)
+ local fspec = "size[8,9]\nlabel[0,0;T21 execution node]\nfield[0.25,1;8,1;channel;Channel prefix;${channel}]\n"
+ fspec = fspec .. "textarea[0.25,2;8,7.5;program;Program;${program}]\n"
+ fspec = fspec .. "button_exit[0,8.5;7.9,1;;Done]\n"
+ meta:set_string("formspec",fspec)
+ meta:set_string("channel","")
+ meta:set_string("program","#This is the default program.")
+ meta:set_string("state","running") -- can be "running", or "waiting"
+ meta:set_string("waitingfor","") -- address waiting for
+ meta:set_int("pc",0)
+ meta:set_int("acc",0)
+ meta:set_int("bak",0)
+ t21_set_infotext(pos)
+ print("Initialized T21 at "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z))
 end
-minetest.register_on_shutdown(test3d.save)
 minetest.register_node("test3d:t21", {
  description = "T21 Execution Node",
  tiles = {
@@ -73,15 +92,15 @@ minetest.register_node("test3d:t21", {
  on_construct = t21_set_meta,
  on_punch = function(pos, _, _, _)
   local meta=minetest.get_meta(pos)
-  local cbeep = meta:get_int("test3d_running")
---  print("cbeep ",cbeep)
-  local nbeep=1
-  if cbeep==1 then
-   nbeep=0
+  local cstate = meta:get_int("test3d_running")
+  local nstate=1
+  if cstate==1 then
+   nstate=0
   else
-   nbeep=1
+   nstate=1
   end
-  meta:set_int("test3d_running",nbeep)
+  print("State: "..tostring(cstate).." -> "..tostring(nstate))
+  meta:set_int("test3d_running",nstate)
  end,
  groups = {snappy=1,choppy=2,oddly_breakable_by_hand=2,flammable=3},
  digiline = {
@@ -91,11 +110,40 @@ minetest.register_node("test3d:t21", {
   }
  },
  on_receive_fields = function(pos,_,fields,sender)
+  if fields.channel == nil or fields.program == nil then return end
   local meta = minetest.get_meta(pos)
-  _G.test3d.states[meta:get_string("statename")].nodes=_G.test3d.states[meta:get_string("statename")].nodes-1 -- decrement node counter
-  meta:set_string("statename",fields.statename)
-  meta:set_string("channel",fields.channel) -- channel the thing listens for commands on
-  _G.test3d.states[meta:get_string("statename")].nodes=_G.test3d.states[meta:get_string("statename")].nodes+1 -- increment new node counter
+  fields.channel = fields.channel or ""
+  meta:set_string("channel",fields.channel)
+  print("Channel: "..fields.channel)
+  local tProgram = {}
+  local lcounter = 0
+  for _,line in ipairs(string.split(fields.program,"\n")) do
+   if lcounter > 14 then break end -- only 15 real lines will be stored
+   local ltab = string.split(line," ")
+   local valid=false
+   if line:sub(1,1) == "#" then valid=true end
+   if line:sub(#line,#line) == ":" then valid=true end
+   for _,ins in ipairs(tInstructions) do
+    if string.upper(ltab[1]) == ins then 
+     valid = true
+    end
+   end
+   if valid then
+    lcounter = lcounter + 1
+    tProgram[#tProgram+1] = line
+    print("Valid: "..line)
+   else
+    print("Invalid: "..line)
+   end
+  end
+  local sProgram = ""
+  for _,l in ipairs(tProgram) do
+   sProgram = sProgram .. l .. "\n"
+  end
+  sProgram = sProgram:sub(1,-1)
+  meta:set_string("program",sProgram)
+  print("Program:\n"..sProgram)
+  meta:set_int("pc",1)
  end
 })
 print("T21 node registered")
@@ -105,23 +153,33 @@ minetest.register_abm({
  interval=1,
  chance=1,
  action = function(pos)
+  function getDigiline(addr)
+   digiline:receptor_send(pos,digilines.rules.default,addr,"get")
+   minetest.get_meta(pos):set_string("state","waiting")
+   minetest.get_meta(pos):set_string("waitingfor",addr)
+  end
   local node = minetest.get_node_or_nil(pos)
   local meta = minetest.get_meta(pos)
-  local beepState = meta:get_int("test3d_running")
-  if beepState == nil then beepState=1 end
---  print(beepState)
-  if beepState == 1 and meta:get_string("statename") ~= nil and meta:get_string("statename") ~= "" then
---[[   minetest.sound_play("default_break_glass",{
-    pos=pos,
-    max_hear_distance=100
-   })
-]]--
-   print("Running T21 node with instance "..tostring(meta:get_string("statename")).." at position "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z))
+  if meta:get_string("state") == "running" then
+   local state = meta:get_int("test3d_running")
+   if state == nil then state=1 end
+   if state == 1 then
+    local pc = meta:get_int("pc")
+    local acc = meta:get_int("acc")
+    local bak = meta:get_int("bak")
+    print("Running T21 node with instance at position "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z).." (PC: "..tostring(pc)..", ACC: "..tostring(acc)..", BAK: "..tostring(bak)..")")
+    local tProgram = string.split(meta:get_string("program"),"\n")
+    local tLine = string.split(tProgram[pc]:upper())
+    if pc == #tProgram then pc = 0 end
+    meta:set_int("pc",pc+1)
+   end
   end
+  t21_set_infotext(pos)
  end,
 })
 print("T21 ABMs registered")
 
+--[[
 minetest.register_chatcommand("lua", { -- I'm a terrible person
  params = "<text>",
  description = "Execute some Lua code",
@@ -131,4 +189,4 @@ minetest.register_chatcommand("lua", { -- I'm a terrible person
   minetest.chat_send_all(tostring(lstr))
  end,
 })
-
+]]--