diff --git a/experiments/example.html b/experiments/example.html
index 35b9837..2303d95 100644
--- a/experiments/example.html
+++ b/experiments/example.html
@@ -3,7 +3,6 @@
 <html>
 <head>
   <title>Todo app</title>
-  <link rel="stylesheet" href="style.css">
 </head>
 
 <body id="body">
@@ -11,9 +10,6 @@
 <div id="ROOT" />
 
 <script type="text/javascript" src="nimcache/example.js"></script>
-<script type="text/javascript">
-  onload(window.location.pathname.split('/')[1])
-</script>
 
 </body>
 </html>
diff --git a/experiments/example.nim b/experiments/example.nim
index 0ea805e..78dcaae 100644
--- a/experiments/example.nim
+++ b/experiments/example.nim
@@ -1,135 +1,33 @@
 
-import vdom, karax, karaxdsl, jdict, jstrutils
-
-type
-  Filter = enum
-    all, active, completed
+import vdom, components, karax, karaxdsl, jdict, jstrutils
 
 var
-  entries: seq[(cstring, bool)]
-  selectedEntry = -1
-  filter: Filter
+  images: seq[cstring] = @[cstring"a", "b", "c", "d"]
 
-proc onTodoEnter(ev: Event; n: VNode) =
-  entries.add((n.value, false))
-  n.value = ""
+proc carousel*(key: VKey): VNode {.component.} =
+  state:
+    var counter = 0
 
-proc removeHandler(ev: Event; n: VNode) =
-  let id = suffixAsInt(n.id, "remove:")
-  entries[id] = (cstring(nil), false)
+  proc next(ev: Event; n: VNode) =
+    counter = (counter + 1) mod images.len
+    markDirty key
 
-proc editHandler(ev: Event; n: VNode) =
-  let id = suffixAsInt(n.id, "edit:")
-  selectedEntry = id
-
-when defined(usecache):
-  var entryCache = newJDict[int, VNode]()
-
-proc focusLost(ev: Event; n: VNode) = selectedEntry = -1
-
-proc editEntry(ev: Event; n: VNode) =
-  let id = suffixAsInt(n.id, "todo-edit:")
-  entries[id][0] = n.value
-  selectedEntry = -1
-
-proc toggleEntry(ev: Event; n: VNode) =
-  let id = suffixAsInt(n.id, "toggle:")
-  entries[id][1] = not entries[id][1]
-
-proc onAllDone(ev: Event; n: VNode) =
-  entries = @[]
-  selectedEntry = -1
-
-proc clearCompleted(ev: Event, n: VNode) =
-  for i in 0..<entries.len:
-    if entries[i][1]: entries[i][0] = nil
-
-proc toClass(completed: bool): cstring =
-  (if completed: cstring"completed" else: cstring"")
-
-proc toVis(visible: bool): cstring =
-  (if visible: cstring"visible" else: "hidden")
-
-proc toChecked(checked: bool): cstring =
-  (if checked: cstring"checked" else: cstring(nil))
-
-proc selected(v: Filter): cstring =
-  (if filter == v: cstring"selected" else: cstring(nil))
-
-proc createEntry(id: int; d: cstring; completed, selected: bool): VNode =
-  # implement caching:
-  when defined(usecache):
-    if entryCache.contains(i):
-      let old = entryCache[i]
-      return old
-
-  result = buildHtml(tr):
-    li(class=toClass(completed)):
-      if not selected:
-        tdiv(class = "view"):
-          input(class = "toggle", `type` = "checkbox", checked = toChecked(completed),
-                onclick=toggleEntry, id="toggle:" & &id)
-          label(onDblClick=editHandler, id="edit:" & &id):
-            text d
-          button(class = "destroy", id="remove:" & $id, onclick=removeHandler)
-      else:
-        input(class = "edit", name = "title", id = "todo-edit:" & &id,
-          onfocusLost = focusLost,
-          onenter = editEntry, value = d)
-  when defined(usecache):
-    entryCache[i] = result
+  result = buildHtml(tdiv(key=key)):
+    text images[counter]
+    button(onclick = next):
+      text "Next"
 
 proc createDom(): VNode =
-  result = buildHtml(tdiv(class="todomvc-wrapper")):
-    section(class = "todoapp"):
-      header(class = "header"):
-        h1:
-          text "todos"
-        input(class = "new-todo", placeholder="What needs to be done?", name = "newTodo",
-              onenter = onTodoEnter)
-      section(class = "main"):
-        input(class = "toggle-all", `type` = "checkbox", name = "toggle")
-        label(`for` = "toggle-all", onclick = onAllDone):
-          text "Mark all as complete"
-        var entriesCount = 0
-        var completedCount = 0
-        ul(class = "todo-list"):
-          for i, d in pairs(entries):
-            if d[0] != nil:
-              let b = case filter
-                      of all: true
-                      of active: not d[1]
-                      of completed: d[1]
-              if b:
-                createEntry(i, d[0], d[1], i == selectedEntry)
-              inc completedCount, ord(d[1])
-              inc entriesCount
-      footer(class = "footer"):
-        span(class = "todo-count"):
-          strong:
-            text(&entriesCount)
-          text cstring" item" & &(if entriesCount != 1: "s left" else: " left")
-        ul(class = "filters"):
-          li:
-            anchor(class = selected(all), href = "#/"):
-              text "All"
-          li:
-            anchor(class = selected(active), href = "#/active"):
-              text "Active"
-          li:
-            anchor(class = selected(completed), href = "#/completed"):
-              text "Completed"
-        button(class = "clear-completed", onclick = clearCompleted):
-          text "Clear completed (" & &completedCount & ")"
+  result = buildHtml(table):
+    tr:
+      td:
+        carousel(0)
+      td:
+        carousel(1)
+    tr:
+      td:
+        carousel(2)
+      td:
+        carousel(3)
 
-setOnHashChange(proc(hash: cstring) =
-  if hash == cstring"#/": filter = all
-  elif hash == cstring"#/completed": filter = completed
-  elif hash == cstring"#/active": filter = active
-)
 setRenderer createDom
-
-proc onload(session: cstring) {.exportc.} =
-  for i in 0..1: # 0_000:
-    entries.add((cstring"Entry " & &i, false))
-  init()
diff --git a/experiments/example.nims b/experiments/example.nims
new file mode 100644
index 0000000..6b5771c
--- /dev/null
+++ b/experiments/example.nims
@@ -0,0 +1 @@
+--path: "../src"
diff --git a/src/components.nim b/src/components.nim
index fbbc00d..54ac8b6 100644
--- a/src/components.nim
+++ b/src/components.nim
@@ -30,6 +30,53 @@ proc addTags() {.compileTime.} =
 static:
   addTags()
 
+template toState(x): untyped = "state" & x
+proc accessState(sv: string): NimNode {.compileTime.} =
+  newTree(nnkBracketExpr, newIdentNode(sv), newIdentNode("key"))
+
+proc stateDecl(n: NimNode; names: TableRef[string, bool]; decl, init: NimNode) =
+  case n.kind
+  of nnkVarSection, nnkLetSection:
+    for c in n:
+      expectKind c, nnkIdentDefs
+      let typ = c[^2]
+      let val = c[^1]
+      let usedType = if typ.kind != nnkEmpty: typ else: val
+      if usedType.kind == nnkEmpty:
+        error(c, "cannot determine the variable's type")
+      for i in 0 .. c.len-3:
+        let v = $c[i]
+        let sv = toState v
+        decl.add quote do:
+          var `sv` = newJDict[VKey, `usedType`]()
+        if val.kind != nnkEmpty:
+          init.add newTree(nnkAsgn, accessState(sv), val)
+        names[v] = true
+  of nnkStmtList, nnkStmtListExpr:
+    for x in n: stateDecl(x, names, decl, init)
+  of nnkDo:
+    stateDecl(n.body, names, decl, init)
+  of nnkCommentStmt: discard
+  else:
+    error(n, "invalid 'state' declaration")
+
+proc doState(n: NimNode; names: TableRef[string, bool]; decl, init: NimNode): NimNode =
+  result = n
+  case n.kind
+  of nnkCallKinds:
+    # handle 'state' declaration and remove it from the AST:
+    if n.len == 2 and repr(n[0]) == "state":
+      stateDecl(n[1], names, decl, init)
+      result = newTree(nnkEmpty)
+  of nnkSym, nnkIdent:
+    let v = $n
+    if v in names:
+      let sv = toState v
+      result = accessState(sv)
+  else:
+    for i in 0..<n.len:
+      result[i] = doState(n[i], names, decl, init)
+
 proc unpack(symbolicType: NimNode; index: int): NimNode {.compileTime.} =
   #let t = symbolicType.getTypeImpl
   let t = repr(symbolicType)
diff --git a/src/karax.nim b/src/karax.nim
index a535ae7..09ec20c 100644
--- a/src/karax.nim
+++ b/src/karax.nim
@@ -75,10 +75,12 @@ proc vnodeToDom(n: VNode): Node =
   elif n.kind == VNodeKind.vthunk:
     let x = callThunk(vcomponents[n.text], n)
     result = vnodeToDom(x)
+    n.key = result.key
     attach n
     return result
   elif n.kind == VNodeKind.dthunk:
     result = callThunk(dcomponents[n.text], n)
+    n.key = result.key
     attach n
     return result
   else:
@@ -114,6 +116,8 @@ proc same(n: VNode, e: Node): bool =
 var
   dorender: proc (): VNode {.closure.}
   currentTree: VNode
+  dirty = newJDict[cstring, bool]()
+  dirtyCount: int
 
 proc replaceById(id: cstring; newTree: Node) =
   let x = document.getElementById(id)
@@ -145,7 +149,27 @@ proc equalsTree(a, b: VNode): bool =
       b.calcHash()
     return a.hash == b.hash
   else:
-    return eq(a, b)
+    result = eq(a, b)
+
+proc markDirty*(key: VKey) =
+  dirty[&key] = true
+  inc dirtyCount
+
+proc updateDirtyElements(parent, current: Node, newNode: VNode) =
+  if newNode.key >= 0 and dirty.contains(&newNode.key):
+    dirty.del(&newNode.key)
+    dec dirtyCount
+    let n = vnodeToDom(newNode)
+    if parent == nil:
+      replaceById("ROOT", n)
+    else:
+      parent.replaceChild(n, current)
+  elif newNode.kind != VNodeKind.text and newNode.kind != VNodeKind.vthunk and
+       newNode.kind != VNodeKind.dthunk:
+    for i in 0..newNode.len-1:
+      updateDirtyElements(current, current[i], newNode[i])
+      # leave early if we know there cannot be anything left to do:
+      #if dirtyCount <= 0: return
 
 proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
   if not equalsShallow(newNode, oldNode):
@@ -217,6 +241,9 @@ proc dodraw() =
     let olddom = document.getElementById("ROOT")
     updateElement(nil, olddom, newtree, currentTree)
     #assert same(newtree, document.getElementById("ROOT"))
+    if dirtyCount > 0:
+      updateDirtyElements(nil, olddom, newtree)
+      dirtyCount = 0
     currentTree = newtree
   # now that it's part of the DOM, give it the focus:
   if toFocus != nil: