diff --git a/factorio-blueprint-generator/src/factory.rs b/factorio-blueprint-generator/src/factory.rs
index a546356..df14f03 100644
--- a/factorio-blueprint-generator/src/factory.rs
+++ b/factorio-blueprint-generator/src/factory.rs
@@ -103,9 +103,9 @@ pub fn generate_factory<L: Layouter, P: Pathfinder + Sync, R: Rng + SeedableRng
                         Beltspeed::from_items_per_second(2.0 * f64::max(c1.amount, c2.amount));
 
                     connections.push(Connection {
-                        startblock: block_index + 1,
+                        startblock: Some(block_index + 1),
                         startpoint: 0,
-                        endblock: block_index,
+                        endblock: Some(block_index),
                         endpoint: if c0_bigger { 0 } else { 1 },
                         lanes: 1,
                         beltspeed,
@@ -335,9 +335,9 @@ pub fn generate_factory<L: Layouter, P: Pathfinder + Sync, R: Rng + SeedableRng
     for (i, c) in factory_graph.factory_connections.iter().enumerate() {
         // dbg!(i, c);
         connections.push(Connection {
-            startblock: intermediate_connections[c.from].1[&i].0,
+            startblock: Some(intermediate_connections[c.from].1[&i].0),
             startpoint: intermediate_connections[c.from].1[&i].1,
-            endblock: intermediate_connections[c.to].0[&i].0,
+            endblock: Some(intermediate_connections[c.to].0[&i].0),
             endpoint: intermediate_connections[c.to].0[&i].1,
             lanes: 1,
             beltspeed: Beltspeed::from_items_per_second(c.amount),
@@ -348,6 +348,8 @@ pub fn generate_factory<L: Layouter, P: Pathfinder + Sync, R: Rng + SeedableRng
     // dbg!(&connections);
 
     let layout_input = LayoutInput {
+        input: Vec::new(),
+        output: Vec::new(),
         blocks,
         connections,
     };
diff --git a/factorio-layout/src/lib.rs b/factorio-layout/src/lib.rs
index 505ad8b..833c7d4 100644
--- a/factorio-layout/src/lib.rs
+++ b/factorio-layout/src/lib.rs
@@ -27,11 +27,12 @@ pub struct Interface {
     pub dir: Direction,
 }
 
+/// None: The static input and output interface of the layout input
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Connection {
-    pub startblock: usize,
+    pub startblock: Option<usize>,
     pub startpoint: usize,
-    pub endblock: usize,
+    pub endblock: Option<usize>,
     pub endpoint: usize,
     pub lanes: usize,
     pub beltspeed: Beltspeed,
@@ -40,6 +41,8 @@ pub struct Connection {
 #[derive(Debug, Serialize, Deserialize)]
 pub struct LayoutInput {
     pub blocks: Vec<MacroBlock>,
+    pub input: Vec<Interface>,
+    pub output: Vec<Interface>,
     pub connections: Vec<Connection>,
 }
 
diff --git a/factorio-layout/src/misc.rs b/factorio-layout/src/misc.rs
index 63c4ff4..81fcad9 100644
--- a/factorio-layout/src/misc.rs
+++ b/factorio-layout/src/misc.rs
@@ -1,10 +1,7 @@
 use crate::{LayoutInput, LayoutResult};
 use factorio_core::prelude::*;
 use factorio_pathfinding::{Connection, examples::HashMapMap};
-use rand::{
-    Rng,
-    seq::IndexedRandom,
-};
+use rand::{Rng, seq::IndexedRandom};
 
 pub fn initally_set_blocks(
     input: &LayoutInput,
@@ -113,20 +110,34 @@ pub fn path_input_from_blocks_positions(
     }
 
     for c in &input.connections {
-        let start_transform = block_positions[c.startblock].block_to_world();
-        let start_pos = input.blocks[c.startblock].output[c.startpoint]
-            .offset
-            .transform(start_transform);
-        let start_dir = input.blocks[c.startblock].output[c.startpoint]
-            .dir
-            .transform(start_transform);
-        let end_transform = block_positions[c.endblock].block_to_world();
-        let end_pos = input.blocks[c.endblock].input[c.endpoint]
-            .offset
-            .transform(end_transform);
-        let end_dir = input.blocks[c.endblock].input[c.endpoint]
-            .dir
-            .transform(end_transform);
+        let start_pos;
+        let start_dir;
+        if let Some(block) = c.startblock {
+            let start_transform = block_positions[block].block_to_world();
+            start_pos = input.blocks[block].output[c.startpoint]
+                .offset
+                .transform(start_transform);
+            start_dir = input.blocks[block].output[c.startpoint]
+                .dir
+                .transform(start_transform);
+        } else {
+            start_pos = input.output[c.startpoint].offset;
+            start_dir = input.output[c.startpoint].dir;
+        }
+        let end_pos;
+        let end_dir;
+        if let Some(block) = c.endblock {
+            let end_transform = block_positions[block].block_to_world();
+            end_pos = input.blocks[block].input[c.endpoint]
+                .offset
+                .transform(end_transform);
+            end_dir = input.blocks[block].input[c.endpoint]
+                .dir
+                .transform(end_transform);
+        } else {
+            end_pos = input.input[c.endpoint].offset;
+            end_dir = input.input[c.endpoint].dir;
+        }
 
         connections.push(Connection {
             start_pos,