diff --git a/activations.py b/activations.py
index 5b1d061..10c5ad2 100644
--- a/activations.py
+++ b/activations.py
@@ -4,7 +4,7 @@ from abc import ABC, abstractmethod
 
 class ActivationFunc(ABC):
     @abstractmethod
-    def derivative(v: np.ndarray) -> np.ndarray:
+    def d(v: np.ndarray) -> np.ndarray:
         pass
 
 
@@ -12,7 +12,7 @@ class ReLU(ActivationFunc):
     def __call__(self, x):
         return x * (x > 0)
 
-    def derivative(self, x):
+    def d(self, x):
         return x > 0
 
 
@@ -23,7 +23,7 @@ class LeakyReLU(ActivationFunc):
     def __call__(self, x):
         return x * (x > 0) + self.k * x * (x <= 0)
 
-    def derivative(self, x):
+    def d(self, x):
         return (x > 0) + self.k * (x <= 0)
 
 
@@ -31,5 +31,5 @@ class Identity(ActivationFunc):
     def __call__(self, x):
         return x
 
-    def derivative(x):
+    def d(x):
         return 1
diff --git a/autoencoder.py b/autoencoder.py
index 42ded53..f4536c0 100644
--- a/autoencoder.py
+++ b/autoencoder.py
@@ -3,43 +3,14 @@ from utils import (dynamic_loss_plot_init,
                    dynamic_loss_plot_update,
                    dynamic_loss_plot_finish)
 from tqdm import tqdm
-from layers import DeepNNLayer
+from layers import DeepNNLayer, SampleLayer
 from activations import ActivationFunc
+from abc import ABC, abstractmethod
 
 LOADER = ['⡿', '⣟', '⣯', '⣷', '⣾', '⣽', '⣻', '⢿']
 
 
-class Autoencoder:
-    def __init__(self,
-                 encoder_layers: list[int],
-                 decoder_layers: list[int],
-                 lr: float,
-                 activation_func: ActivationFunc):
-        if encoder_layers[-1] != decoder_layers[0]:
-            raise Exception(
-                f"Encoder output and decoder input don't match {encoder_layers[-1]} != {encoder_layers[0]}" # noqa
-            )
-        self.encoder = DeepNNLayer(encoder_layers, lr, activation_func)
-        self.decoder = DeepNNLayer(decoder_layers, lr, activation_func)
-
-    def __str__(self):
-        return f'Encoder:\n{self.encoder}\n\nDecoder:\n{self.decoder}'
-
-    def loss(self, data_set: list[np.ndarray]) -> float:
-        loss = 0
-        for x in data_set:
-            loss += np.sum(np.abs(x - self.forward(x)[0])) / len(x)
-        return loss / len(data_set)
-
-    def train(self, v: np.ndarray):
-        out = self.decoder.forward(
-            self.encoder.forward(v)
-        )
-        self.encoder.backprop(
-            self.decoder.backprop(out - v)
-        )
-        return np.sum(np.abs(out - v)) / len(v)
-
+class AAutoencoder(ABC):
     def train_dataset(self,
                       data_set: list[np.ndarray],
                       max_epoch: int,
@@ -80,6 +51,60 @@ class Autoencoder:
             dynamic_loss_plot_finish(ax, line)
         return losses
 
+    def save(self, path: str):
+        path = path.removesuffix('.npy')
+        np.save(path, self)
+
+    def load(path: str) -> 'ClassicalAutoencoder':
+        path = path.removesuffix('.npy') + '.npy'
+        data = np.load(path, allow_pickle=True)
+        return data.item()
+
+    @abstractmethod
+    def loss(self, data_set: list[np.ndarray]) -> float:
+        pass
+
+    @abstractmethod
+    def train(self, v: np.ndarray) -> float:
+        pass
+
+    @abstractmethod
+    def forward(self, v: np.ndarray) -> np.ndarray:
+        pass
+
+
+class ClassicalAutoencoder(AAutoencoder):
+    def __init__(self,
+                 encoder_layers: list[int],
+                 decoder_layers: list[int],
+                 lr: float,
+                 activation_func: ActivationFunc):
+        if encoder_layers[-1] != decoder_layers[0]:
+            raise Exception(
+                f"Encoder output and decoder input don't match {encoder_layers[-1]} != {encoder_layers[0]}" # noqa
+            )
+        self.encoder = DeepNNLayer(encoder_layers, lr, activation_func)
+        self.decoder = DeepNNLayer(decoder_layers, lr, activation_func)
+
+    def __str__(self):
+        return f'Encoder:\n{self.encoder}\n\nDecoder:\n{self.decoder}'
+
+    def loss(self, data_set: list[np.ndarray]) -> float:
+        loss = 0
+        for x in data_set:
+            loss += np.sum(np.abs(x - self.forward(x)[0])) / len(x)
+        return loss / len(data_set)
+
+    def train(self, v: np.ndarray):
+        out = self.decoder.forward(
+            self.encoder.forward(v)
+        )
+        error = out - v
+        self.encoder.backprop(
+            self.decoder.backprop(error)
+        )
+        return np.sum(np.abs(error)) / len(v)
+
     def encode(self, v: np.ndarray) -> np.ndarray:
         return self.encoder.forward(v)
 
@@ -91,11 +116,39 @@ class Autoencoder:
         out = self.decode(code)
         return out, code
 
-    def save(self, path: str):
-        path = path.removesuffix('.npy')
-        np.save(path, self)
 
-    def load(path: str) -> 'Autoencoder':
+class VariationalAutoencoder(AAutoencoder):
+    def __init__(self,
+                 encoder_layers: list[int],
+                 decoder_layers: list[int],
+                 sampling_size: int,
+                 lr: float,
+                 activation_func: ActivationFunc):
+        if encoder_layers[-1] != decoder_layers[0]:
+            raise Exception(
+                f"Encoder output and decoder input don't match {encoder_layers[-1]} != {encoder_layers[0]}" # noqa
+            )
+        self.encoder = DeepNNLayer(encoder_layers, lr, activation_func)
+        self.decoder = DeepNNLayer(decoder_layers, lr, activation_func)
+        self.sampler = SampleLayer(self.encoder.out_size, lr, activation_func)
+        self.sampling_size = sampling_size
+
+    def load(path: str) -> 'ClassicalAutoencoder':
         path = path.removesuffix('.npy') + '.npy'
         data = np.load(path, allow_pickle=True)
         return data.item()
+
+    def train(self, v: np.ndarray) -> float:
+        out_enc = self.encoder.forward(v)
+        in_samples = np.zeros(
+                (self.sampling_size, self.encoder.out_size)
+            )
+        out_samples = np.zeros(
+                (self.sampling_size, self.decoder.out_size)
+            )
+        for i in range(self.sampling_size):
+            in_samples[i] = self.sampler.forward(out_enc)
+            out_samples[i] = self.decoder.forward(in_samples[i])
+
+    def forward(self, v: np.ndarray) -> np.ndarray:
+        pass
diff --git a/layers.py b/layers.py
index c70d105..1e88a66 100644
--- a/layers.py
+++ b/layers.py
@@ -20,8 +20,8 @@ class NNLayer:
     def __str__(self):
         return f'[ {self.W.shape[0]} => {self.W.shape[1]}\tlr:{self.lr}\tactivation:{self.activation_func.__class__.__name__} ]' # noqa
 
-    def forward(self, V: np.ndarray) -> np.ndarray:
-        self.input = normalize(V)
+    def forward(self, v: np.ndarray) -> np.ndarray:
+        self.input = normalize(v)
         self.output_linear = self.input @ self.W + self.B
         self.output = self.activation_func(
                 self.output_linear
@@ -38,6 +38,33 @@ class NNLayer:
         return ret
 
 
+class SampleLayer:
+    def __init__(self,
+                 in_size: int,
+                 lr: float,
+                 activation_func: ActivationFunc):
+        self.input = None
+        self.mean_nn = NNLayer(
+            in_size,
+            in_size,
+            lr,
+            activation_func)
+        self.std_nn = NNLayer(
+            in_size,
+            in_size,
+            lr,
+            activation_func)
+
+    def forward(self, v: np.ndarray) -> np.ndarray:
+        self.input = v
+        mean = self.mean_nn.forward(v)
+        std = self.std_nn.forward(v)
+        return np.random.normal(mean, std, 1)
+
+    def backprop(self, errors: np.ndarray) -> np.ndarray:
+        pass
+
+
 class DeepNNLayer:
     def __init__(self,
                  layers: list[int],
@@ -52,6 +79,8 @@ class DeepNNLayer:
                         lr,
                         activation_func)
                 )
+        self.in_size = layers[0]
+        self.out_size = layers[-1]
 
     def __str__(self):
         return '\n'.join([str(layer) for layer in self.layers])
diff --git a/mnist_test.py b/mnist_test.py
index b9f788b..5714473 100644
--- a/mnist_test.py
+++ b/mnist_test.py
@@ -1,6 +1,6 @@
 import matplotlib.pyplot as plt
 import numpy as np
-from autoencoder import Autoencoder
+from autoencoder import ClassicalAutoencoder
 from activations import LeakyReLU
 import os
 
@@ -21,7 +21,7 @@ def mnist_train(
         filename: str,
         max_epoch: int,
         patience: int,
-        ) -> Autoencoder:
+        ) -> ClassicalAutoencoder:
     x_train, _, x_test, _ = load_mnist()
     in_len = x_train[0].shape[0] * x_train[0].shape[0]
     x_train.resize(x_train.shape[0], in_len)
@@ -29,9 +29,9 @@ def mnist_train(
     x_train = x_train / 255
     x_test = x_test / 255
     if os.path.exists(filename):
-        autoencoder = Autoencoder.load(filename)
+        autoencoder = ClassicalAutoencoder.load(filename)
     else:
-        autoencoder = Autoencoder(
+        autoencoder = ClassicalAutoencoder(
             [in_len, 64, 16],
             [16, 64, in_len],
             0.01,
@@ -46,7 +46,7 @@ def mnist_train(
     return autoencoder
 
 
-def mnist_test(model: str | Autoencoder):
+def mnist_test(model: str | ClassicalAutoencoder):
     x_train, _, x_test, y_test = load_mnist()
     in_len = x_train[0].shape[0] * x_train[0].shape[0]
     img_shape = x_train[0].shape
@@ -55,7 +55,7 @@ def mnist_test(model: str | Autoencoder):
     x_train = x_train / 255
     x_test = x_test / 255
     if isinstance(model, str):
-        autoencoder: Autoencoder = Autoencoder.load(model)
+        autoencoder: ClassicalAutoencoder = ClassicalAutoencoder.load(model)
     else:
         autoencoder = model
     print(autoencoder)