diff --git a/neural/apis/state.lua b/neural/apis/state.lua
new file mode 100644
index 0000000..1d27804
--- /dev/null
+++ b/neural/apis/state.lua
@@ -0,0 +1,158 @@
+-- credit: https://github.com/kyleconroy/lua-state-machine
+
+local machine = {}
+machine.__index = machine
+
+local NONE = "none"
+local ASYNC = "async"
+
+local function call_handler(handler, params)
+  if handler then
+    return handler(unpack(params))
+  end
+end
+
+local function create_transition(name)
+  local can, to, from, params
+
+  local function transition(self, ...)
+    if self.asyncState == NONE then
+      can, to = self:can(name)
+      from = self.current
+      params = { self, name, from, to, ...}
+
+      if not can then return false end
+      self.currentTransitioningEvent = name
+
+      local beforeReturn = call_handler(self["onbefore" .. name], params)
+      local leaveReturn = call_handler(self["onleave" .. from], params)
+
+      if beforeReturn == false or leaveReturn == false then
+        return false
+      end
+
+      self.asyncState = name .. "WaitingOnLeave"
+
+      if leaveReturn ~= ASYNC then
+        transition(self, ...)
+      end
+
+      return true
+    elseif self.asyncState == name .. "WaitingOnLeave" then
+      self.current = to
+
+      local enterReturn = call_handler(self["onenter" .. to] or self["on" .. to], params)
+
+      self.asyncState = name .. "WaitingOnEnter"
+
+      if enterReturn ~= ASYNC then
+        transition(self, ...)
+      end
+
+      return true
+    elseif self.asyncState == name .. "WaitingOnEnter" then
+      call_handler(self["onafter" .. name] or self["on" .. name], params)
+      call_handler(self["onstatechange"], params)
+      self.asyncState = NONE
+      self.currentTransitioningEvent = nil
+      return true
+    else
+      if string.find(self.asyncState, "WaitingOnLeave") or string.find(self.asyncState, "WaitingOnEnter") then
+        self.asyncState = NONE
+        transition(self, ...)
+        return true
+      end
+    end
+
+    self.currentTransitioningEvent = nil
+    return false
+  end
+
+  return transition
+end
+
+local function add_to_map(map, event)
+  if type(event.from) == 'string' then
+    map[event.from] = event.to
+  else
+    for _, from in ipairs(event.from) do
+      map[from] = event.to
+    end
+  end
+end
+
+function machine.create(options)
+  assert(options.events)
+
+  local fsm = {}
+  setmetatable(fsm, machine)
+
+  fsm.options = options
+  fsm.current = options.initial or 'none'
+  fsm.asyncState = NONE
+  fsm.events = {}
+
+  for _, event in ipairs(options.events or {}) do
+    local name = event.name
+    fsm[name] = fsm[name] or create_transition(name)
+    fsm.events[name] = fsm.events[name] or { map = {} }
+    add_to_map(fsm.events[name].map, event)
+  end
+
+  for name, callback in pairs(options.callbacks or {}) do
+    fsm[name] = callback
+  end
+
+  return fsm
+end
+
+function machine:is(state)
+  return self.current == state
+end
+
+function machine:can(e)
+  local event = self.events[e]
+  local to = event and event.map[self.current] or event.map['*']
+  return to ~= nil, to
+end
+
+function machine:cannot(e)
+  return not self:can(e)
+end
+
+function machine:todot(filename)
+  local dotfile = io.open(filename,'w')
+  dotfile:write('digraph {\n')
+  local transition = function(event,from,to)
+    dotfile:write(string.format('%s -> %s [label=%s];\n',from,to,event))
+  end
+  for _, event in pairs(self.options.events) do
+    if type(event.from) == 'table' then
+      for _, from in ipairs(event.from) do
+        transition(event.name,from,event.to)
+      end
+    else
+      transition(event.name,event.from,event.to)
+    end
+  end
+  dotfile:write('}\n')
+  dotfile:close()
+end
+
+function machine:transition(event)
+  if self.currentTransitioningEvent == event then
+    return self[self.currentTransitioningEvent](self)
+  end
+end
+
+function machine:cancelTransition(event)
+  if self.currentTransitioningEvent == event then
+    self.asyncState = NONE
+    self.currentTransitioningEvent = nil
+  end
+end
+
+machine.NONE = NONE
+machine.ASYNC = ASYNC
+
+return machine
diff --git a/neural/fisher.lua b/neural/fisher.lua
index 5eb4195..d666f75 100644
--- a/neural/fisher.lua
+++ b/neural/fisher.lua
@@ -1,3 +1,5 @@
+local machine = require('neural.state')
+
 local device = _G.device
 local os     = _G.os
 
@@ -19,51 +21,98 @@ local depth = -3
 local icon
 local scales = { .2, .4, .6, .8, 1, .8, .6, .4 }
 local scale = 0
+local w, h
 
 if canvas then
-  local w, h = canvas.getSize()
+  w, h = canvas.getSize()
   icon = canvas.addItem({ w - 20, h - 20 }, 'minecraft:fishing_rod' )
 end
 
+local fsm = machine.create({
+  events = {
+    { name = 'startup', from = 'none',    to = 'wait' },
+    { name = 'rod',     from = 'wait',    to = 'idle' },
+    { name = 'norod',   from = 'idle',    to = 'wait' },
+    { name = 'norod',   from = 'fishing', to = 'wait' },
+    { name = 'cast',    from = 'idle',    to = 'fishing' },
+    { name = 'reel',    from = 'fishing', to = 'idle' },
+  },
+
+  callbacks = {
+    -- events
+    oncast = function()
+      kinetic.use(.2)
+      os.sleep(.5)
+      local meta = sensor.getMetaByName('unknown')
+      depth = meta and meta.y - .5 or depth
+      return true
+    end,
+
+    onreel =  function()
+      kinetic.use(.3)
+      os.sleep(.5)
+      return true
+    end,
+
+    -- state changes
+    onenterwait = function()
+      print('waitng for fishing rod to be selected')
+      if icon then
+        icon.remove()
+        icon = canvas.addItem({ w - 20, h - 20 }, 'minecraft:fishing_rod' )
+      end
+    end,
+
+    onleavewait = function()
+      print('fishing...')
+    end,
+
+    onenterfishing = function()
+      if icon then
+        icon.remove()
+        scale = 0
+        icon = canvas.addItem({ w - 20, h - 20 }, 'minecraft:fish', math.random(0, 3) )
+      end
+    end,
+  }
+})
+
+local function isHoldingRod()
+  local owner = sensor.getMetaOwner()
+  local held = owner.heldItem and owner.heldItem.getMetadata()
+  return held and held.rawName == 'item.fishingRod'
+end
+
 local function fish()
+  fsm:startup()
   while true do
     local meta = sensor.getMetaByName('unknown')
-    if not meta then
-      local owner = sensor.getMetaOwner()
-      local held = owner.heldItem and owner.heldItem.getMetadata()
-      if held and held.rawName == 'item.fishingRod' then
-        if icon then
-          icon.setItem('minecraft:fish', math.random(0, 3))
-        end
-        kinetic.use(.2)
-        print('casting')
-        os.sleep(.5)
-        meta = sensor.getMetaByName('unknown')
-        depth = meta and meta.y - .5 or depth
-      else
-        if icon then
-          icon.setItem('minecraft:fishing_rod')
-          icon.setScale(1)
-        end
-        print('waiting for fishing rod to be selected')
-      end
-      os.sleep(1)
-    else
-      if meta.y < depth then
-        kinetic.use(.3)
-        print('reeled in')
-      end
-      if icon then
-        scale = scale + 1
-        icon.setScale(scales[(scale % #scales) + 1])
+    if isHoldingRod() then
+      fsm:rod()
+      if not meta then
+        fsm:cast()
+      elseif meta and meta.y < depth then
+        fsm:reel()
       end
       os.sleep(.1)
+    else
+      fsm:norod()
+      os.sleep(1)
+    end
+
+    if icon and fsm.current == 'fishing' then
+      scale = scale + 1
+      icon.setScale(scales[(scale % #scales) + 1])
     end
   end
 end
 
-pcall(fish)
+local s, m = pcall(fish)
 
 if icon then
   icon.remove()
-end
\ No newline at end of file
+end
+
+if not s and m then
+  error(m)
+end