diff --git a/init.lua b/init.lua
index a26d388..3bef31a 100644
--- a/init.lua
+++ b/init.lua
@@ -1,5 +1,5 @@
 local Tactree = {}
-Tactree.Nodes = {}
+local Nodes = {}
 
 local function NodeStart(node, args)
 	-- abort if started
@@ -32,13 +32,13 @@ end
 local function default_impl(node) end
 function Tactree.Leaf(name)
 	return function(t)
-		if Tactree.Nodes[name] then
+		if Nodes[name] then
 			error('node with name \'' .. name .. '\' already exists.',  2)
 		else
-			Tactree.Nodes[name] = {}
+			Nodes[name] = {}
 		end
 
-		local node_type = Tactree.Nodes[name]
+		local node_type = Nodes[name]
 
 		local tick = t.tick or t[1]
 		if type(tick) ~= 'function' then error('no tick function supplied', 2) end
@@ -52,14 +52,14 @@ end
 function Tactree.Composite(name)
 	return function(parent_type_name)
 		return function(children)
-			if Tactree.Nodes[name] then
+			if Nodes[name] then
 				error('node with name \'' .. name .. '\' already exists.',  2)
 			else
-				if not Tactree.Nodes[parent_type_name] then error('no such node \'' .. name .. '\'', 2) end
-				Tactree.Nodes[name] = setmetatable({}, Tactree.Nodes[parent_type_name])
+				if not Nodes[parent_type_name] then error('no such node \'' .. name .. '\'', 2) end
+				Nodes[name] = setmetatable({}, { __index = Nodes[parent_type_name] })
 			end
 
-			local node_type = Tactree.Nodes[name]
+			local node_type = Nodes[name]
 
 			node_type.children = {}
 
@@ -73,7 +73,7 @@ function Tactree.Composite(name)
 end
 
 function Tactree.Tree(name)
-	if not Tactree.Nodes[name] then error('no such node \'' .. name .. '\'', 2) end
+	if not Nodes[name] then error('no such node \'' .. name .. '\'', 2) end
 
 	local node = {}
 	node.children = {}
@@ -81,15 +81,59 @@ function Tactree.Tree(name)
 	node.update = NodeUpdate
 	node.private = NodePrivateData
 
-	if Tactree.Nodes[name].children then
-		for _, child in ipairs(Tactree.Nodes[name].children) do
-			table.insert(node.children, Tactree.Tree(child))
+	-- this will crash if there is a recursive structure
+	-- find a way to prevent this?
+	if Nodes[name].children then
+		for _, child in ipairs(Nodes[name].children) do
+			local cn = Tactree.Tree(child)
+			cn.parent = node
+			table.insert(node.children, cn)
 		end
 	end
 
-	return setmetatable(node, { __index = Tactree.Nodes[name] })
+	return setmetatable(node, { __index = Nodes[name] })
 end
 
+Tactree.Leaf 'Sequence'
+{
+	start = function(node)
+		node:private().current_child = 1
+		node.children[node:private().current_child]:start()
+	end,
+	tick = function(node)
+		local result = node.children[node:private().current_child]:update()
+
+		if type(result) == 'boolean' then
+			if result then
+				if node:private().current_child == #node.children then
+					return true
+				else
+					node:private().current_child = node:private().current_child + 1
+					node.children[node:private().current_child]:start()
+				end
+			else
+				return false
+			end
+		end
+	end
+}
+
+Tactree.Leaf 'Repeat'
+{
+	start = function(node)
+		node.children[1]:start()
+	end,
+	tick = function(node)
+		local result = node.children[1]:update()
+
+		if type(result) == 'boolean' then
+			if not result then return false end
+
+			node.children[1]:start()
+		end
+	end
+}
+
 --[[
 	Example usage
 	-------------