diff --git a/server/Cargo.toml b/server/Cargo.toml
index 629de4b..78550ed 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -8,6 +8,7 @@ edition = "2021"
 [dependencies]
 anyhow = "1.0.75"
 axum = "0.7.2"
+bincode = "1.3.3"
 bit-struct = "0.3.2"
 const_format = "0.2.32"
 erased-serde = "0.4.1"
diff --git a/server/Makefile b/server/Makefile
index e33165d..257cef3 100644
--- a/server/Makefile
+++ b/server/Makefile
@@ -1,13 +1,14 @@
-DEVPORT=1505
-DEVFILE="offline-state.json"
+DEVPORT=1507
+DEVFILE="dev"
 PRODPORT=48228
-PRODFILE="state.json"
+PRODFILE="prod"
 
 MANIFEST=../Cargo.toml
 
 .PHONY: local global
 local: surnames.txt names.txt ipaddr.txt
 	echo '"localhost"' > ipaddr.txt
+	mkdir -p dev
 	cargo run $(DEVPORT) $(DEVFILE)
 	 
 global: surnames.txt names.txt ipaddr.txt
diff --git a/server/src/main.rs b/server/src/main.rs
index 86f3fed..d6107e8 100644
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -1,6 +1,6 @@
 #![feature(iter_map_windows)]
 
-use std::{collections::VecDeque, io::ErrorKind, sync::Arc, env::args};
+use std::{collections::VecDeque, io::ErrorKind, sync::Arc, env::args, path};
 
 use anyhow::{Context, Error, Ok};
 use axum::{
@@ -73,7 +73,7 @@ impl LiveState {
 }
 
 static PORT: OnceCell<u16> = OnceCell::const_new();
-static SAVE: OnceCell<String> = OnceCell::const_new();
+static SAVE: OnceCell<path::PathBuf> = OnceCell::const_new();
 
 type SharedControl = Arc<RwLock<LiveState>>;
 
@@ -85,24 +85,11 @@ async fn main() -> Result<(), Error> {
         None => 48228,
     })?;
     SAVE.set(match args.next() {
-        Some(file) => file,
-        None => "state.json".to_string(),
+        Some(file) => file.into(),
+        None => "save".into(),
     })?;
 
-    let state = match tokio::fs::OpenOptions::new()
-        .read(true)
-        .open(SAVE.get().unwrap())
-        .await
-    {
-        tokio::io::Result::Ok(file) => serde_json::from_reader(file.into_std().await)?,
-        tokio::io::Result::Err(e) => match e.kind() {
-            ErrorKind::NotFound => SavedState {
-                turtles: Vec::new(),
-                world: RTree::new(),
-            },
-            _ => panic!(),
-        },
-    };
+    let state = read_from_disk().await?;
 
     let state = LiveState::from_save(state);
 
@@ -142,11 +129,42 @@ async fn flush(State(state): State<SharedControl>) -> &'static str {
 }
 
 async fn write_to_disk(state: SavedState) -> anyhow::Result<()> {
-    let json = serde_json::to_string_pretty(&state)?;
-    tokio::fs::write(SAVE.get().unwrap(), json).await?;
+    let json = serde_json::to_string_pretty(&state.turtles)?;
+    let bincode = bincode::serialize(&state.world)?;
+    tokio::fs::write(SAVE.get().unwrap().join("turtles.json"), json).await?;
+    tokio::fs::write(SAVE.get().unwrap().join("world.bin"), bincode).await?;
     Ok(())
 }
 
+async fn read_from_disk() -> anyhow::Result<SavedState> {
+    let turtles = match tokio::fs::OpenOptions::new()
+        .read(true)
+        .open(SAVE.get().unwrap().join("turtles.json"))
+        .await
+    {
+        tokio::io::Result::Ok(file) => serde_json::from_reader(file.into_std().await)?,
+        tokio::io::Result::Err(e) => match e.kind() {
+            ErrorKind::NotFound => Vec::new(),
+            _ => panic!(),
+        },
+    };
+
+    let world = match tokio::fs::OpenOptions::new()
+    .read(true).open(SAVE.get().unwrap().join("world.bin")).await {
+        tokio::io::Result::Ok(file) => bincode::deserialize_from(file.into_std().await)?,
+        tokio::io::Result::Err(e) => match e.kind() {
+            ErrorKind::NotFound => RTree::new(),
+            _ => panic!(),
+        },
+        
+    };
+
+    Ok(SavedState {
+        turtles,
+        world,
+    })
+}
+
 async fn create_turtle(
     State(state): State<SharedControl>,
     Json(req): Json<turtle::TurtleRegister>,
diff --git a/server/src/turtle.rs b/server/src/turtle.rs
index 1cd12db..e9a21ee 100644
--- a/server/src/turtle.rs
+++ b/server/src/turtle.rs
@@ -274,7 +274,8 @@ impl TurtleCommander {
                 if let TurtleCommandResponse::Failure =  state.ret {
                     if let TurtleCommand::Backward(_) = command {
                         // turn around if you bump your rear on something
-                        self.goto(Position::new(recent.pos, recent.dir.left().left())).await?
+                        self.execute(TurtleCommand::Left).await;
+                        recent = self.execute(TurtleCommand::Left).await.pos;
                     }
                     break 'route;
                 }
@@ -305,13 +306,13 @@ pub(crate) async fn process_turtle_update(
 
     if turtle.fuel > update.fuel {
         let diff = turtle.fuel - update.fuel;
-        turtle.fuel = update.fuel;
 
         let delta = turtle.queued_movement * diff as i32;
 
         turtle.position.pos += delta;
         turtle.queued_movement = Vec3::zeros();
     }
+    turtle.fuel = update.fuel;
 
     let above = Block {
         name: update.above.clone(),