diff --git a/lib/csys/program.ex b/lib/csys/program.ex
index 18c4aca..90f958b 100644
--- a/lib/csys/program.ex
+++ b/lib/csys/program.ex
@@ -3,11 +3,16 @@ defmodule Scopes.CSys.Program do
   alias Scopes.Shape
 
   defmodule State do
-    defstruct [:value, :stage, :prog]
+    defstruct [:value, :threshold, :stage, :prog]
   end
 
-  def prepare(prog, value \\ []) do
-    state = %State{value: value, stage: :initial, prog: prog}
+  def prepare(prog, args) do
+    state = %State{
+      value: args[:value], 
+      threshold: args[:threshold], 
+      stage: :initial, 
+      prog: prog
+    }
     {state, get_proc(state)}
   end
 
@@ -37,8 +42,8 @@ defmodule Scopes.CSys.Program do
     {stages, transitions}
   end
 
-  def prepare_basic(value \\ []) do
-    prepare(basic_prog(), value)
+  def prepare_basic(args \\ [value: 0, threshold: 0]) do
+    prepare(basic_prog(), args)
   end
 
   # basic processors
@@ -53,11 +58,12 @@ defmodule Scopes.CSys.Program do
 
   def basic(msg, scope) do
     case Shape.head(msg) do
+      [:csys, :set | _rest] -> set(msg, scope)
+      #[:csys, :data | rest] -> process_data(rest, Shape.data(msg), scope)
       [:csys, :connect | _rest] -> CSys.connect(msg, scope)
       [:csys, :create, :succ | _rest] -> create_succ(msg, scope)
       [:csys, :create, :pred | _rest] -> create_pred(msg, scope)
       #[:csys, :next | _rest] -> next(scope, meta)
-      #[:csys, :data | rest] -> process_data(rest, Shape.data(msg), scope)
       #[:csys, action | rest] -> transition(action, scope)
       _ -> CSys.forward(msg, scope) || CSys.notify(msg, scope)
     end
@@ -65,6 +71,15 @@ defmodule Scopes.CSys.Program do
 
 # message handlers // proc steps
 
+  def set(msg, scope) do
+    data = Shape.data(msg)
+    state = CSys.state(scope)
+    value = data[:value] || state.value
+    threshold = data[:threshold] || state.threshold
+    state_n = %{state | value: value, threshold: threshold}
+    CSys.update(put_elem(scope, 0, state_n))
+  end
+
   def create_succ(msg, scope) do
     new = CSys.create(msg, restart(scope))
     data = Shape.data(msg)
@@ -77,6 +92,15 @@ defmodule Scopes.CSys.Program do
     CSys.send_message(new, [:csys, :connect], Map.put(data, :target, self()))
   end
 
+# synapse operations
+
+  def negate() do
+    fn msg ->
+      value = Shape.data(msg)[:value] || 0
+      Shape.create(Shape.head(msg), data: %{Shape.data(msg) | value: -value})
+    end
+  end
+
 # helper functions
 
   def restart({state, _proc, syns, env}) do
diff --git a/test/csys_test.exs b/test/csys_test.exs
index ef80b44..8c1eac6 100644
--- a/test/csys_test.exs
+++ b/test/csys_test.exs
@@ -24,22 +24,25 @@ defmodule Scopes.CSysTest do
     test "minimal-neural-net" do
       _env = Environ.setup(Program.prepare_basic())
       zero = receive_data([:csys, :created]).new
-      CSys.send_value(zero, "Hello Zero!")
-      assert "Hello Zero!" = receive_data().value
-      CSys.send_message(zero, [:csys, :create, :pred], %{op: neg_only()})
-      new1 = receive_data([:csys, :created]).new
-      CSys.send_message(new1, [:csys, :create, :succ], %{op: CSys.data_only()})
-      new2 = receive_data([:csys, :created]).new
+      CSys.send_value(zero, 0)
+      assert 0 = receive_data().value
+      #CSys.send_message(zero, [:csys, :create, :pred], %{op: neg_only()})
+      CSys.send_message(zero, [:csys, :create, :pred], %{op: Program.negate()})
+      one = receive_data([:csys, :created]).new
+      CSys.send_message(one, [:csys, :create, :succ], %{op: CSys.data_only()})
+      two = receive_data([:csys, :created]).new
       Process.sleep(1)
-      CSys.send_value(new1, "Hello New1!")
-      assert "Hello New1!" = receive_data().value
-      CSys.send_message(new2, [:csys, :create, :pred])
-      new3 = receive_data([:csys, :created]).new
-      CSys.send_message(new3, [:csys, :connect], %{target: zero})
+      CSys.send_value(one, 1)
+      #assert 1 = receive_data().value
+      assert Enum.member?([-1, 1], receive_data().value)
+      assert Enum.member?([-1, 1], receive_data().value)
+      CSys.send_message(two, [:csys, :create, :pred])
+      three = receive_data([:csys, :created]).new
+      CSys.send_message(three, [:csys, :connect], %{target: zero})
       Process.sleep(1)
-      CSys.send_value(new3, "Hello New3!")
-      assert "Hello New3!" = receive_data().value
-      assert "Hello New3!" = receive_data().value
+      CSys.send_value(three, 3)
+      assert 3 = receive_data().value
+      assert 3 = receive_data().value
       Process.sleep(50)
       refute_received msg, "unhandled message(s): #{inspect(msg)}"
     end