diff --git a/experiment1/model.py b/experiment1/model.py
new file mode 100644
index 0000000..8e66786
--- /dev/null
+++ b/experiment1/model.py
@@ -0,0 +1,45 @@
+import torch as T
+from pytorch_lightning import LightningModule
+from torch import nn
+from torch.nn.parameter import Parameter
+
+from experiment1.modules import Adder, Substracter
+
+
+class Modular1(LightningModule):
+    def __init__(self):
+        """Modular AI approach 1"""
+        super().__init__()
+
+        # Usable modules
+        self.adder = Adder()
+        self.substracter = Substracter()
+
+        # Model weights
+        self.weights_adder = Parameter(data=T.rand(1), requires_grad=True)
+        self.weights_substracter = Parameter(data=T.rand(1), requires_grad=True)
+
+        # Loss
+        self.criteria = nn.L1Loss()
+
+    def forward(self, x):
+        y0 = self.adder(x)
+        y1 = self.substracter(x)
+        y = self.weights_adder * y0 + self.weights_substracter * y1
+        return y
+
+    def training_step(self, batch, batch_idx, *args, **kwargs) -> T.Tensor:
+        # Unpacking
+        samples = batch["samples"]
+        targets = batch["targets"]
+
+        # Forward
+        targets_pred = self(samples)
+
+        # Loss
+        loss = self.criteria(targets, targets_pred)
+
+        # Logging
+        self.log("loss/train", loss, prog_bar=True, on_step=False, on_epoch=True)
+        return loss
+