diff --git a/gears/connections.py b/gears/connections.py
index c73f812..31624d7 100644
--- a/gears/connections.py
+++ b/gears/connections.py
@@ -1,4 +1,4 @@
-from typing import Any, Hashable, TypeVar, Callable
+from typing import Any, Hashable, Optional, TypeVar, Callable
 
 from gears.effect import effect_of
 from gears.gear import Gear
@@ -8,6 +8,8 @@ def connect[S: Hashable, T: Hashable](
     source: Gear[S],
     to_target_val: Callable[[S], T],
     to_source: Callable[[S, T], S],
+    # i_know_what_im_doing: Optional[bool] = None,
+    i_know_what_im_doing: Optional[bool] = True,
 ) -> Gear[T]:
     target = Gear(to_target_val(source()))
 
@@ -20,7 +22,10 @@ def connect[S: Hashable, T: Hashable](
     def set_target_val(source_val: S):
         nonlocal entry_guard
         if entry_guard:
-            return
+            if i_know_what_im_doing:
+                return
+            else:
+                raise ValueError("You have a bad bidirectional mapping")
         entry_guard = True
         try:
             target.set(to_target_val(source_val))
@@ -31,7 +36,10 @@ def connect[S: Hashable, T: Hashable](
     def set_source_val(target_val: T):
         nonlocal entry_guard
         if entry_guard:
-            return
+            if i_know_what_im_doing:
+                return
+            else:
+                raise ValueError("You have a bad bidirectional mapping")
         entry_guard = True
         try:
             source.set(to_source(source(), target_val))
diff --git a/gears/gear.py b/gears/gear.py
index 4aa5438..6212949 100644
--- a/gears/gear.py
+++ b/gears/gear.py
@@ -5,6 +5,7 @@ class Gear[T: Hashable]:
     def __init__(self, value: T):
         self._value = value
         self.effects = []
+        self.connection_effects = []
 
     def get(self) -> T:
         return self._value
@@ -13,8 +14,11 @@ class Gear[T: Hashable]:
         return self.get()
 
     def set(self, value: T):
+        print("setty: ", value)
         if value == self._value:
             return
         self._value = value
+        for effect in self.connection_effects:
+            effect.on_change(value)
         for effect in self.effects:
             effect.on_change(value)
diff --git a/tests/test_signals.py b/tests/test_signals.py
index 5b7af55..2116d1c 100644
--- a/tests/test_signals.py
+++ b/tests/test_signals.py
@@ -1,9 +1,11 @@
 from dataclasses import dataclass
 from typing import NamedTuple
 from unittest.mock import MagicMock
+
+import pytest
 from gears import Gear
 from gears.connections import connect
-from gears.effect import effect_of, effect_of_2
+from gears.effect import Effect, effect_of, effect_of_2
 
 
 def test_get_set():
@@ -28,6 +30,9 @@ def test_basic_effect():
 
     assert last_arg == "E"
 
+    g.set("hello")
+    assert last_arg == "hello"
+
 
 def test_effect_of_2():
     g1 = Gear("E")
@@ -54,15 +59,87 @@ def test_connect():
     assert my_str() == "321"
 
 
+# def test_dualis():
+#     val_both: Gear[tuple[int, int]] = Gear((5, 6))
+#     val0 = connect(val_both, lambda both: both[0], lambda both, val0: (val0, both[1]))
+#     val1 = connect(val_both, lambda both: both[1], lambda both, val1: (both[0], val1))
+
+
+def test_watts():
+    volts = Gear(3.0)
+    amps = Gear(5.0)
+
+    @effect_of_2(volts, amps)
+    def on_watts_changed(volts: float, amps: float):
+        watts = volts * amps
+        if watts > 100:
+            raise ValueError("OMG ITS BURNING")
+
+    volts.set(5.0)
+    with pytest.raises(ValueError):
+        volts.set(50.0)
+
+
+def test_led():
+    battery_voltage = Gear(3.0)
+    switch: Gear[bool] = Gear(True)  # true means circuit closed
+    # ohms_circuit = Gear(1.0)
+    ohms_circuit = connect(
+        switch, lambda x: 1.0 if x else 100000000.0, lambda _, y: y < 100
+    )
+
+    log: list[str] = []
+
+    @effect_of_2(battery_voltage, ohms_circuit)
+    def on_led_inputs_changed(volts: float, ohms: float):
+        amps = volts / ohms
+        if amps > 1:
+            print("LED ACTIVE!")
+            log.append("LED ACTIVE!")
+        else:
+            print("LED INACTIVE!")
+            log.append("LED INACTIVE!")
+
+    # Effect(on_led_inputs_changed, battery_voltage, led_ohms)
+
+    assert log == ["LED ACTIVE!"]
+    switch.set(False)
+    assert log == ["LED ACTIVE!", "LED INACTIVE!"]
+
+
 def test_connect_multiplication():
     mul1 = Gear(10.0)
     mul2 = connect(mul1, lambda x: x * 2.0, lambda _, y: y / 2.0)
+    mul4 = connect(mul2, lambda x: x * 2.0, lambda _, y: y / 2.0)
     mul3 = connect(mul1, lambda x: x * 3.0, lambda _, y: y / 3.0)
     assert mul2() == 20
     assert mul3() == 30
     mul2.set(30)
     assert mul1() == 15
     assert mul3() == 45
+    assert mul4() == 60
+
+    # mul1
+    # |> mul2
+    #   |> mul4
+    # |> mul3
+    #
+
+
+class Person:
+    name: str
+
+
+class HouseHold:
+    people: list[Person]
+
+
+class NameEntry:
+    def __init__(self, name: Gear[str]):
+        # self.name = name
+        textBox = TextBox(...)
+        effect_of(name)(textBox.setValue)
+        textBox.onChange = name.set
 
 
 def test_connect_property():