diff --git a/README.md b/README.md
index 01f8447..d8421ab 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,56 @@ Implementation of Alpha Fold 3 from the paper: "Accurate structure prediction of
 ## install
 `$pip install alphafold3`
 
+## Input Tensor Size Example
+
+```python
+import torch
+
+# Define the batch size, number of nodes, and number of features
+batch_size = 1
+num_nodes = 5
+num_features = 64
+
+# Generate random pair representations using torch.randn
+# Shape: (batch_size, num_nodes, num_nodes, num_features)
+pair_representations = torch.randn(
+    batch_size, num_nodes, num_nodes, num_features
+)
+
+# Generate random single representations using torch.randn
+# Shape: (batch_size, num_nodes, num_features)
+single_representations = torch.randn(
+    batch_size, num_nodes, num_features
+)
+```
+
+## Genetic Diffusion
+Need review but basically it operates on atomic coordinates.
+
+```python
+import torch
+from alphafold3.diffusion import GeneticDiffusionModule
+
+# Create an instance of the GeneticDiffusionModule
+model = GeneticDiffusionModule(channels=3, training=True)
+
+# Generate random input coordinates
+input_coords = torch.randn(10, 100, 100, 3)
+
+# Generate random ground truth coordinates
+ground_truth = torch.randn(10, 100, 100, 3)
+
+# Pass the input coordinates and ground truth coordinates through the model
+output_coords, loss = model(input_coords, ground_truth)
+
+# Print the output coordinates
+print(output_coords)
+
+# Print the loss value
+print(loss)
+```
+
+
 # Citation
 ```bibtex
 @article{Abramson2024-fj,
@@ -35,6 +85,10 @@ Implementation of Alpha Fold 3 from the paper: "Accurate structure prediction of
 ```
 
 
+
+sequences, ligands, ,covalent bonds -> input embedder [3] -> 
+
+
 # Todo
 
 - [ ] Implement Figure A, implement triangle update, transition, 
diff --git a/alphafold3/model.py b/alphafold3/model.py
index d4abf48..275233d 100644
--- a/alphafold3/model.py
+++ b/alphafold3/model.py
@@ -539,3 +539,24 @@ def __init__(
             dim_head=dim_head,
             dropout=dropout,
         )
+
+
+
+
+class AlphaFold3(nn.module):
+    def __init__(self, dim: int):
+        super().__init__()
+        self.dim = dim
+        
+        self.confidence_projection = nn.Linear(dim, 1)
+    
+    def forward(
+        self,
+        pair_representation: Tensor,
+        single_representation: Tensor,
+        return_loss: bool = False,
+        ground_truth: Tensor = None,
+        return_confidence: bool = False
+    ) -> Tensor:
+        pass
+    
\ No newline at end of file
diff --git a/alphafold3/pair_transition.py b/alphafold3/pair_transition.py
new file mode 100644
index 0000000..1a34782
--- /dev/null
+++ b/alphafold3/pair_transition.py
@@ -0,0 +1,99 @@
+# Copyright 2021 AlQuraishi Laboratory
+# Copyright 2021 DeepMind Technologies Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from typing import Optional
+
+import torch
+import torch.nn as nn
+
+from torch.nn import Linear, LayerNorm
+from openfold.utils.chunk_utils import chunk_layer
+
+
+class PairTransition(nn.Module):
+    """
+    Implements Algorithm 15.
+    """
+
+    def __init__(self, c_z, n):
+        """
+        Args:
+            c_z:
+                Pair transition channel dimension
+            n:
+                Factor by which c_z is multiplied to obtain hidden channel
+                dimension
+        """
+        super(PairTransition, self).__init__()
+
+        self.c_z = c_z
+        self.n = n
+
+        self.layer_norm = LayerNorm(self.c_z)
+        self.linear_1 = Linear(self.c_z, self.n * self.c_z, init="relu")
+        self.relu = nn.ReLU()
+        self.linear_2 = Linear(self.n * self.c_z, c_z, init="final")
+
+    def _transition(self, z, mask):
+        # [*, N_res, N_res, C_z]
+        z = self.layer_norm(z)
+        
+        # [*, N_res, N_res, C_hidden]
+        z = self.linear_1(z)
+        z = self.relu(z)
+
+        # [*, N_res, N_res, C_z]
+        z = self.linear_2(z) 
+        z = z * mask
+
+        return z
+
+    @torch.jit.ignore
+    def _chunk(self,
+        z: torch.Tensor,
+        mask: torch.Tensor,
+        chunk_size: int,
+    ) -> torch.Tensor:
+        return chunk_layer(
+            self._transition,
+            {"z": z, "mask": mask},
+            chunk_size=chunk_size,
+            no_batch_dims=len(z.shape[:-2]),
+        )
+
+    def forward(self, 
+        z: torch.Tensor, 
+        mask: Optional[torch.Tensor] = None,
+        chunk_size: Optional[int] = None,
+    ) -> torch.Tensor:
+        """
+        Args:
+            z:
+                [*, N_res, N_res, C_z] pair embedding
+        Returns:
+            [*, N_res, N_res, C_z] pair embedding update
+        """
+        # DISCREPANCY: DeepMind forgets to apply the mask in this module.
+        if mask is None:
+            mask = z.new_ones(z.shape[:-1])
+
+        # [*, N_res, N_res, 1]
+        mask = mask.unsqueeze(-1)
+
+        if chunk_size is not None:
+            z = self._chunk(z, mask, chunk_size)
+        else:
+            z = self._transition(z=z, mask=mask)
+
+        return z
\ No newline at end of file
diff --git a/diffusion_example.py b/diffusion_example.py
new file mode 100644
index 0000000..bca9656
--- /dev/null
+++ b/diffusion_example.py
@@ -0,0 +1,20 @@
+import torch
+from alphafold3.diffusion import GeneticDiffusionModule
+
+# Create an instance of the GeneticDiffusionModule
+model = GeneticDiffusionModule(channels=3, training=True)
+
+# Generate random input coordinates
+input_coords = torch.randn(10, 100, 100, 3)
+
+# Generate random ground truth coordinates
+ground_truth = torch.randn(10, 100, 100, 3)
+
+# Pass the input coordinates and ground truth coordinates through the model
+output_coords, loss = model(input_coords, ground_truth)
+
+# Print the output coordinates
+print(output_coords)
+
+# Print the loss value
+print(loss)
diff --git a/input_type.py b/input_type.py
index 7519669..fb9e9af 100644
--- a/input_type.py
+++ b/input_type.py
@@ -1,12 +1,18 @@
 import torch
 
+# Define the batch size, number of nodes, and number of features
 batch_size = 1
 num_nodes = 5
 num_features = 64
 
+# Generate random pair representations using torch.randn
+# Shape: (batch_size, num_nodes, num_nodes, num_features)
 pair_representations = torch.randn(
     batch_size, num_nodes, num_nodes, num_features
 )
+
+# Generate random single representations using torch.randn
+# Shape: (batch_size, num_nodes, num_features)
 single_representations = torch.randn(
     batch_size, num_nodes, num_features
 )
diff --git a/pyproject.toml b/pyproject.toml
index 3c27547..5190309 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -26,6 +26,7 @@ python = "^3.10"
 zetascale = "*"
 torch = "*"
 einops = "*"
+openfold = "*"
 
 
 [tool.poetry.group.lint.dependencies]