diff --git a/turtle/equipment/turtle_device.py b/turtle/equipment/turtle_device.py
index 8de0663..27ee251 100644
--- a/turtle/equipment/turtle_device.py
+++ b/turtle/equipment/turtle_device.py
@@ -3,11 +3,14 @@ from typing import Optional, Collection, Any
 from controls.device import SynchronyDevice
 from controls.device import TraitDescriptor
 from controls.device import ActionDescriptor
+from controls.device import DeviceError
 import inspect
 
+
 class TurtleDevice(SynchronyDevice):
     def open(self):
         self.turtle = Turtle()
+        self.descriptors = dict(traits=dict(), actions=dict())
         super().open()
 
     def close(self):
@@ -22,20 +25,36 @@ class TurtleDevice(SynchronyDevice):
 
     def __getitem__(self, trait_name: str) -> Optional[Any]:
         """Return logical state of trait `trait_name`."""
-        pass
+        return self.descriptors[trait_name]
+
+    def read_descriptors(self, arg):
+        self.descriptors = self.get_descriptors()
+        return self.descriptors
 
     def read(self, trait_name: str) -> Any:
-        pass
+        """Read physical state of trait `trait_name` from device."""
+        self.read_descriptors()
+        return self.descriptors[trait_name]
 
     def write(self, trait_name: str, value: Any) -> bool:
-        self.turtle.write()
+        """Turtle traits are not writable"""
+        # trait_desc = self.trait_descriptors.get(trait_name)
+        # if trait_desc.writable:
+        #     return getattr(self.turtle, trait_name)(value)
+        super().write()
 
     def execute(self, action_name: str, *args, **kwargs):
         """Execute action `action_name`, using `args` and `kwargs` as action argument."""
-        pass
+        action = self.get_descriptors()["actions"].get(action_name)
+        if action:
+            return getattr(self.turtle, action_name)(*args, **kwargs)
+        super().execute()
 
     def invalidate(self, trait_name: str):
-        pass
+        """Invalidate logical state of trait `trait_name`"""
+        if self.trait_descriptors.get(trait_name):
+            self.trait_descriptors[trait_name] = None
+        raise DeviceError()
 
     def get_descriptors(self):
         descriptors = dict(actions=dict(), traits=dict())