diff --git a/src/fot/esh.rs b/src/fot/esh.rs
index 06a7492..33a70ba 100644
--- a/src/fot/esh.rs
+++ b/src/fot/esh.rs
@@ -18,6 +18,10 @@ pub struct ESHEntityFlags {
     pub flags: u16,
 }
 
+impl ESHEntityFlags {
+    const SIZE: usize = 4;
+}
+
 #[derive(Debug)]
 pub struct ESHFrame {
     pub unk1: Vec<u8>,
@@ -26,6 +30,10 @@ pub struct ESHFrame {
     pub c: f32,
 }
 
+impl ESHFrame {
+    const SIZE: usize = 48;
+}
+
 #[derive(Debug)]
 pub struct ESHRect {
     pub top: i32,
@@ -34,6 +42,10 @@ pub struct ESHRect {
     pub bottom: i32,
 }
 
+impl ESHRect {
+    const SIZE: usize = 16;
+}
+
 #[derive(Debug)]
 pub enum ESHValue {
     Unknown(ESHUnknown),
@@ -75,8 +87,7 @@ impl Decoder for ESHValue {
             Self::TYPE_STRING => ESHValue::String(rd.read::<FString>(0)?),
             Self::TYPE_SPRITE => ESHValue::Sprite(rd.read::<FString>(0)?),
             Self::TYPE_ESBIN => {
-                let bin_size = rd.read_u32()?;
-                ESHValue::Binary(rd.read_bytes(bin_size as usize)?)
+                ESHValue::Binary(rd.read_bytes(data_size as usize)?)
             }
             Self::TYPE_ENTTITYFLAGS => {
                 let entity_id = rd.read_u16()?;
@@ -156,14 +167,14 @@ impl Decoder for ESHValue {
             }
             ESHValue::EntityFlags(eflags) => {
                 wd.write_u32(Self::TYPE_ENTTITYFLAGS)?;
-                wd.write_u32(4)?;
+                wd.write_u32(ESHEntityFlags::SIZE as u32)?;
 
                 wd.write_u16(eflags.entity_id)?;
                 wd.write_u16(eflags.flags)?;
             }
             ESHValue::Frame(frame) => {
                 wd.write_u32(Self::TYPE_FRAME)?;
-                wd.write_u32(0x24)?;
+                wd.write_u32(ESHFrame::SIZE as u32)?;
 
                 wd.write_bytes(&frame.unk1);
                 wd.write_f32(frame.c / 4.)?;
@@ -172,7 +183,7 @@ impl Decoder for ESHValue {
             }
             ESHValue::Rect(rect) => {
                 wd.write_u32(Self::TYPE_RECT)?;
-                wd.write_u32(0x10)?;
+                wd.write_u32(ESHRect::SIZE as u32)?;
 
                 wd.write_i32(rect.top)?;
                 wd.write_i32(rect.left)?;
@@ -194,9 +205,9 @@ impl Decoder for ESHValue {
                 ESHValue::String(str) => str.get_enc_size(),
                 ESHValue::Sprite(spr) => spr.get_enc_size(),
                 ESHValue::Binary(bin) => bin.len(),
-                ESHValue::EntityFlags(_) => 4,
-                ESHValue::Frame(_) => 0x30,
-                ESHValue::Rect(_) => 0x10,
+                ESHValue::EntityFlags(_) => ESHEntityFlags::SIZE,
+                ESHValue::Frame(_) => ESHFrame::SIZE,
+                ESHValue::Rect(_) => ESHRect::SIZE,
             }
     }
 }
diff --git a/src/fot/stream.rs b/src/fot/stream.rs
index 237658e..4c75a1f 100644
--- a/src/fot/stream.rs
+++ b/src/fot/stream.rs
@@ -98,8 +98,8 @@ impl WriteStream {
     }
 
     pub fn write_bytes(&mut self, bytes: &[u8]) {
-        self.buf.get_mut().extend(bytes.iter());
         self.skip(bytes.len());
+        self.buf.get_mut().extend(bytes.iter());
     }
 
     pub fn write<T: Decoder>(&mut self, val: &T) -> Result<()> {
diff --git a/src/fot/world.rs b/src/fot/world.rs
index 860bf9d..cba022c 100644
--- a/src/fot/world.rs
+++ b/src/fot/world.rs
@@ -35,9 +35,15 @@ impl World {
         let esh: ESH = rd.read(0)?;
         dbg!(&esh);
 
+        let esh1 = Raw {
+            offset: 0,
+            size: 0,
+            mem: self.data.mem[0x14AC..0x14AC+esh.get_enc_size()].to_vec()
+        };
+        esh1.dump(Path::new("esh1.bin"))?;
         let esh2 = esh.encode()?;
         esh2.dump(Path::new("esh2.bin"))?;
-        assert_eq!(&self.data.mem[0x14AC..0x14AC+esh.get_enc_size()], &esh2.mem, "ESH encoding test passed");
+        assert_eq!(esh1.mem, esh2.mem, "ESH encoding test passed");
 
         Ok(())
     }