diff --git a/.yardopts b/.yardopts
index 873ce10..f6020b9 100644
--- a/.yardopts
+++ b/.yardopts
@@ -1 +1 @@
-*.rb --private --exclude old/* 
+--private --exclude old/* 
diff --git a/lib/rcircuit.rb b/lib/rcircuit.rb
new file mode 100644
index 0000000..4115996
--- /dev/null
+++ b/lib/rcircuit.rb
@@ -0,0 +1,7 @@
+require_relative "rcircuit/port.rb"
+require_relative "rcircuit/gate.rb"
+require_relative "rcircuit/device.rb"
+require_relative "rcircuit/not.rb"
+require_relative "rcircuit/and.rb"
+require_relative "rcircuit/or.rb"
+require_relative "rcircuit/xor.rb"
diff --git a/and.rb b/lib/rcircuit/and.rb
similarity index 88%
rename from and.rb
rename to lib/rcircuit/and.rb
index a42cfdd..34f40ae 100644
--- a/and.rb
+++ b/lib/rcircuit/and.rb
@@ -1,6 +1,3 @@
-require_relative "gate.rb"
-require_relative "port.rb"
-
 # Represents an AND gate
 class AndGate < Gate
 
diff --git a/lib/rcircuit/device.rb b/lib/rcircuit/device.rb
new file mode 100644
index 0000000..bd0018c
--- /dev/null
+++ b/lib/rcircuit/device.rb
@@ -0,0 +1,47 @@
+# Class for devices such as adders and registers
+class Device
+  # Add an input port
+  # @param name [String] Name of the port
+  # @param width [Integer] Width of the port
+  # @return [void]
+  def add_input(name, width=1)
+    self.class.class_eval{attr_reader name.to_sym}
+    port = Port.new(width)
+    instance_variable_set("@#{name}", port)
+    port.add_callback { |val| on_change(val) }
+  end
+
+  # Add an output port
+  # @param name [String] Name of the port
+  # @param width [Integer] Width of the port
+  # @return [void]
+  def add_output(name, width=1)
+    self.class.class_eval{attr_reader name.to_sym}
+    port = Port.new(width)
+    instance_variable_set("@#{name}", port)
+  end
+
+  # Add a subdevice
+  # @param name [String] Name of the subdevice
+  # @param device [Device] Device to add
+  # @return [void]
+  def define_device(name, device)
+    instance_variable_set("@#{name}", device)
+    self.class.class_eval{attr_reader name.to_sym}
+  end
+
+  private
+  # Used to set the ports from the argument hash in initialize
+  # @param hash [Hash{String=>Port}] Hash of names to ports
+  # @return [void]
+  def init_assign(hash)
+    hash.each do |name, port|
+      #check if there is a defined method (port) that matches
+      if self.respond_to?(name)
+        method(name).call(port)
+      else
+        raise ArgumentError, "No defined input '#{name}'"
+      end
+    end
+  end
+end
diff --git a/gate.rb b/lib/rcircuit/gate.rb
similarity index 98%
rename from gate.rb
rename to lib/rcircuit/gate.rb
index a2897da..e1bc01f 100644
--- a/gate.rb
+++ b/lib/rcircuit/gate.rb
@@ -1,5 +1,3 @@
-require_relative "port.rb"
-
 # @abstract Subclass and override {#inputs_changed} to implement a gate
 ## Base class for gates
 class Gate
diff --git a/not.rb b/lib/rcircuit/not.rb
similarity index 92%
rename from not.rb
rename to lib/rcircuit/not.rb
index 2cfaf6a..3eb23c8 100644
--- a/not.rb
+++ b/lib/rcircuit/not.rb
@@ -1,6 +1,3 @@
-require_relative "gate.rb"
-require_relative "port.rb"
-
 # Represents a NOT gate
 class NotGate < Gate
 
diff --git a/or.rb b/lib/rcircuit/or.rb
similarity index 85%
rename from or.rb
rename to lib/rcircuit/or.rb
index 2e1517c..ba78b4e 100644
--- a/or.rb
+++ b/lib/rcircuit/or.rb
@@ -1,6 +1,3 @@
-require_relative "gate.rb"
-require_relative "port.rb"
-
 # Represents an OR gate
 class OrGate < Gate
 
diff --git a/port.rb b/lib/rcircuit/port.rb
similarity index 91%
rename from port.rb
rename to lib/rcircuit/port.rb
index 238dc8d..c09d68d 100644
--- a/port.rb
+++ b/lib/rcircuit/port.rb
@@ -12,11 +12,8 @@ class Port
   attr_reader :width
 
   # Returns a new instance of Port
-  # @overload set(width)
-  #   @param width [Integer] The width of the port
-  # @overload set(width, name)
-  #   @param width [Integer] The width of the port
-  #   @param name [String] The name of the port
+  # @param width [Integer] The width of the port
+  # @param name [String] The name of the port
   def initialize(width, name="")
     @connected=[]
     @callbacks=[]
diff --git a/xor.rb b/lib/rcircuit/xor.rb
similarity index 86%
rename from xor.rb
rename to lib/rcircuit/xor.rb
index 3e9728c..aeb9b1d 100644
--- a/xor.rb
+++ b/lib/rcircuit/xor.rb
@@ -1,6 +1,3 @@
-require_relative "gate.rb"
-require_relative "port.rb"
-
 # Represents an XOR gate
 class XorGate < Gate
 
diff --git a/spec/and_spec.rb b/spec/and_spec.rb
index 08291ef..62bfaad 100644
--- a/spec/and_spec.rb
+++ b/spec/and_spec.rb
@@ -1,4 +1,3 @@
-require_relative "../and.rb"
 describe AndGate do
   it "should AND together all inputs" do
     table=[
diff --git a/spec/gate_spec.rb b/spec/gate_spec.rb
index 9865048..416071c 100644
--- a/spec/gate_spec.rb
+++ b/spec/gate_spec.rb
@@ -1,6 +1,3 @@
-require_relative "../port.rb"
-require_relative "../gate.rb"
-
 describe Gate do
   let(:klass) do
     Class.new(Gate) do
diff --git a/spec/not_spec.rb b/spec/not_spec.rb
index 6fd21a8..b26d63f 100644
--- a/spec/not_spec.rb
+++ b/spec/not_spec.rb
@@ -1,4 +1,3 @@
-require_relative "../not.rb"
 describe NotGate do
   it "should NOT the input" do
     table=[
diff --git a/spec/or_spec.rb b/spec/or_spec.rb
index 384d121..c6996e5 100644
--- a/spec/or_spec.rb
+++ b/spec/or_spec.rb
@@ -1,4 +1,3 @@
-require_relative "../or.rb"
 describe OrGate do
   it "should OR together all inputs" do
     table=[
diff --git a/spec/port_spec.rb b/spec/port_spec.rb
index 9c6b977..9ce56d7 100644
--- a/spec/port_spec.rb
+++ b/spec/port_spec.rb
@@ -1,5 +1,3 @@
-require_relative "../port.rb"
-
 describe Port do
   it "should set the port's value when we call #setval" do
     a=Port.new(4)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..a1b33b5
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1 @@
+require_relative "../lib/rcircuit.rb"
diff --git a/spec/xor_spec.rb b/spec/xor_spec.rb
index ffad5db..bd9d4d7 100644
--- a/spec/xor_spec.rb
+++ b/spec/xor_spec.rb
@@ -1,4 +1,3 @@
-require_relative "../xor.rb"
 describe XorGate do
   it "should XOR together all inputs" do
     table=[