diff --git a/src/techblox/blocks/block_entity.rs b/src/techblox/blocks/block_entity.rs
index 926400a..22efdcd 100644
--- a/src/techblox/blocks/block_entity.rs
+++ b/src/techblox/blocks/block_entity.rs
@@ -1,3 +1,5 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent};
 use crate::techblox::blocks::{DBEntityStruct, PositionEntityStruct, ScalingEntityStruct, RotationEntityStruct,
 SkewComponent, GridRotationStruct, SerializedGridConnectionsEntityStruct, SerializedBlockPlacementInfoStruct,
@@ -75,3 +77,13 @@ impl SerializedEntityDescriptor for BlockEntity {
         Self::hash("StandardBlockEntityDescriptorV4") // 1357220432
     }
 }
+
+impl AsRef<BlockEntity> for BlockEntity {
+    fn as_ref(&self) -> &Self {
+        self
+    }
+}
+
+pub trait Block: SerializedEntityDescriptor + AsRef<BlockEntity> {}
+
+impl Block for BlockEntity {}
diff --git a/src/techblox/blocks/common_components.rs b/src/techblox/blocks/common_components.rs
index 9e87d43..15bb660 100644
--- a/src/techblox/blocks/common_components.rs
+++ b/src/techblox/blocks/common_components.rs
@@ -106,7 +106,7 @@ impl SerializedEntityComponent for SerializedColourParameterEntityStruct {}
 /// Block group component.
 #[derive(Copy, Clone, Parsable)]
 pub struct BlockGroupEntityComponent {
-    /// Index of colour in Techblox palette
+    /// Index of block in Techblox block groups (deserialized in earlier part of game save)
     pub current_block_group: i32,
 }
 
diff --git a/src/techblox/blocks/engine.rs b/src/techblox/blocks/engine.rs
index 35f6bde..06715a4 100644
--- a/src/techblox/blocks/engine.rs
+++ b/src/techblox/blocks/engine.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity}};
+blocks::{BlockEntity, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Engine entity descriptor
@@ -33,6 +35,14 @@ impl SerializedEntityDescriptor for EngineBlockEntity {
     }
 }
 
+impl AsRef<BlockEntity> for EngineBlockEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for EngineBlockEntity {}
+
 /// Engine settings entity component.
 #[derive(Copy, Clone, Parsable)]
 pub struct EngineBlockTweakableComponent  {
diff --git a/src/techblox/blocks/joint.rs b/src/techblox/blocks/joint.rs
index 14ca192..ff221b0 100644
--- a/src/techblox/blocks/joint.rs
+++ b/src/techblox/blocks/joint.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity}};
+blocks::{BlockEntity, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Joint block entity descriptor
@@ -26,3 +28,11 @@ impl SerializedEntityDescriptor for JointBlockEntity {
         Self::hash("JointBlockEntityDescriptorV3") // 3586818581
     }
 }
+
+impl AsRef<BlockEntity> for JointBlockEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for JointBlockEntity {}
diff --git a/src/techblox/blocks/lookup_tables.rs b/src/techblox/blocks/lookup_tables.rs
index bcb695d..b82f467 100644
--- a/src/techblox/blocks/lookup_tables.rs
+++ b/src/techblox/blocks/lookup_tables.rs
@@ -1,6 +1,6 @@
 use std::io::Read;
 
-use crate::techblox::{Parsable, SerializedEntityDescriptor};
+use crate::techblox::{Parsable};
 use crate::techblox::blocks::*;
 
 const HASHNAMES: &[&str] = &[
@@ -70,7 +70,8 @@ const HASHNAMES: &[&str] = &[
     "CharacterCameraEntityDescriptorV1",
 ];
 
-pub fn lookup_hashname(hash: u32, data: &mut dyn Read) -> std::io::Result<Box<dyn SerializedEntityDescriptor>> {
+pub fn lookup_hashname(hash: u32, data: &mut dyn Read) ->
+    std::io::Result<Box<dyn Block>> {
     Ok(match hash {
         1357220432 /*StandardBlockEntityDescriptorV4*/ => Box::new(BlockEntity::parse(data)?),
         2281299333 /*PilotSeatEntityDescriptorV4*/ => Box::new(PilotSeatEntity::parse(data)?),
diff --git a/src/techblox/blocks/mod.rs b/src/techblox/blocks/mod.rs
index e1f926c..19ce4c6 100644
--- a/src/techblox/blocks/mod.rs
+++ b/src/techblox/blocks/mod.rs
@@ -12,7 +12,7 @@ mod tyre;
 mod wheel_rig;
 mod wire_entity;
 
-pub use block_entity::{BlockEntity};
+pub use block_entity::{BlockEntity, Block};
 pub use common_components::{DBEntityStruct, PositionEntityStruct, ScalingEntityStruct, RotationEntityStruct,
 SkewComponent, GridRotationStruct, SerializedGridConnectionsEntityStruct, SerializedBlockPlacementInfoStruct,
 SerializedCubeMaterialStruct, SerializedUniformBlockScaleEntityStruct, SerializedColourParameterEntityStruct,
diff --git a/src/techblox/blocks/passenger_seat.rs b/src/techblox/blocks/passenger_seat.rs
index 9110a15..7175b36 100644
--- a/src/techblox/blocks/passenger_seat.rs
+++ b/src/techblox/blocks/passenger_seat.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity, SeatFollowCamComponent}};
+blocks::{BlockEntity, SeatFollowCamComponent, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Passenger seat entity descriptor (V4)
@@ -32,3 +34,11 @@ impl SerializedEntityDescriptor for PassengerSeatEntity {
         Self::hash("PassengerSeatEntityDescriptorV4") // 1360086092
     }
 }
+
+impl AsRef<BlockEntity> for PassengerSeatEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for PassengerSeatEntity {}
diff --git a/src/techblox/blocks/pilot_seat.rs b/src/techblox/blocks/pilot_seat.rs
index c454c3e..3510f83 100644
--- a/src/techblox/blocks/pilot_seat.rs
+++ b/src/techblox/blocks/pilot_seat.rs
@@ -1,4 +1,6 @@
-use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent, blocks::BlockEntity};
+use std::convert::AsRef;
+
+use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent, blocks::{BlockEntity, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Pilot seat entity descriptor (V4)
@@ -32,6 +34,14 @@ impl SerializedEntityDescriptor for PilotSeatEntity {
     }
 }
 
+impl AsRef<BlockEntity> for PilotSeatEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for PilotSeatEntity {}
+
 /// Seat settings entity component.
 #[derive(Copy, Clone, Parsable)]
 pub struct SeatFollowCamComponent {
diff --git a/src/techblox/blocks/spring.rs b/src/techblox/blocks/spring.rs
index fb888a6..ea23f3e 100644
--- a/src/techblox/blocks/spring.rs
+++ b/src/techblox/blocks/spring.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity}};
+blocks::{BlockEntity, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Damped angular spring entity descriptor
@@ -37,6 +39,14 @@ impl SerializedEntityDescriptor for DampedAngularSpringEntity {
     }
 }
 
+impl AsRef<BlockEntity> for DampedAngularSpringEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for DampedAngularSpringEntity {}
+
 /// Damped spring entity descriptor
 #[derive(Copy, Clone, Parsable)]
 pub struct DampedSpringEntity {
@@ -72,6 +82,14 @@ impl SerializedEntityDescriptor for DampedSpringEntity {
     }
 }
 
+impl AsRef<BlockEntity> for DampedSpringEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for DampedSpringEntity {}
+
 /// Joint settings entity component.
 #[derive(Copy, Clone, Parsable)]
 pub struct TweakableJointDampingComponent  {
diff --git a/src/techblox/blocks/tyre.rs b/src/techblox/blocks/tyre.rs
index bc6a248..6889cae 100644
--- a/src/techblox/blocks/tyre.rs
+++ b/src/techblox/blocks/tyre.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity}};
+blocks::{BlockEntity, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Tire entity descriptor
@@ -26,3 +28,11 @@ impl SerializedEntityDescriptor for TyreEntity {
         Self::hash("TyreEntityDescriptorV1") // 1517625162
     }
 }
+
+impl AsRef<BlockEntity> for TyreEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for TyreEntity {}
diff --git a/src/techblox/blocks/wheel_rig.rs b/src/techblox/blocks/wheel_rig.rs
index 9622eef..ecda159 100644
--- a/src/techblox/blocks/wheel_rig.rs
+++ b/src/techblox/blocks/wheel_rig.rs
@@ -1,5 +1,7 @@
+use std::convert::AsRef;
+
 use crate::techblox::{SerializedEntityDescriptor, Parsable, SerializedEntityComponent,
-blocks::{BlockEntity, TweakableJointDampingComponent}};
+blocks::{BlockEntity, TweakableJointDampingComponent, Block}};
 use libfj_parsable_macro_derive::*;
 
 /// Wheel rig entity descriptor
@@ -37,6 +39,14 @@ impl SerializedEntityDescriptor for WheelRigEntity {
     }
 }
 
+impl AsRef<BlockEntity> for WheelRigEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block
+    }
+}
+
+impl Block for WheelRigEntity {}
+
 /// Wheel rig entity descriptor
 #[derive(Copy, Clone, Parsable)]
 pub struct WheelRigSteerableEntity {
@@ -68,6 +78,14 @@ impl SerializedEntityDescriptor for WheelRigSteerableEntity {
     }
 }
 
+impl AsRef<BlockEntity> for WheelRigSteerableEntity {
+    fn as_ref(&self) -> &BlockEntity {
+        &self.block.as_ref()
+    }
+}
+
+impl Block for WheelRigSteerableEntity {}
+
 /// Wheel rig settings entity component.
 #[derive(Copy, Clone, Parsable)]
 pub struct WheelRigTweakableStruct  {
diff --git a/src/techblox/entity_traits.rs b/src/techblox/entity_traits.rs
index 407310d..c3ec1f8 100644
--- a/src/techblox/entity_traits.rs
+++ b/src/techblox/entity_traits.rs
@@ -1,4 +1,5 @@
 use std::io::{Read, Write};
+use std::any::Any;
 
 /// Standard trait for parsing Techblox game save data.
 pub trait Parsable {
@@ -26,7 +27,7 @@ pub trait SerializedEntityDescriptor: Parsable {
 
 /// Serializable entity component.
 /// Components are the atomic unit of entities.
-pub trait SerializedEntityComponent: Parsable {
+pub trait SerializedEntityComponent: Parsable + Any {
     /// Raw size of struct, in bytes.
     fn size() -> usize where Self: Sized {
         std::mem::size_of::<Self>()
diff --git a/src/techblox/gamesave.rs b/src/techblox/gamesave.rs
index 7668dca..7f863ea 100644
--- a/src/techblox/gamesave.rs
+++ b/src/techblox/gamesave.rs
@@ -1,9 +1,9 @@
 use chrono::{naive::NaiveDate, Datelike};
 use std::io::{Read, Write};
 
-use crate::techblox::{EntityHeader, BlockGroupEntity, parse_i64, parse_u32, Parsable, SerializedEntityDescriptor,
+use crate::techblox::{EntityHeader, BlockGroupEntity, parse_i64, parse_u32, Parsable,
 SerializedFlyCamEntity, SerializedPhysicsCameraEntity};
-use crate::techblox::blocks::{lookup_hashname, SerializedWireEntity, SerializedGlobalWireSettingsEntity};
+use crate::techblox::blocks::{lookup_hashname, SerializedWireEntity, SerializedGlobalWireSettingsEntity, Block};
 
 /// A collection of cubes and other data from a GameSave.techblox file
 //#[derive(Clone)]
@@ -37,7 +37,7 @@ pub struct GameSave {
     pub cube_headers: Vec<EntityHeader>,
 
     /// Blocks
-    pub cube_entities: Vec<Box<dyn SerializedEntityDescriptor>>,
+    pub cube_entities: Vec<Box<dyn Block>>,
 
     /// Amount of wires in the save data, as claimed by the file.
     pub wire_len: u32,
@@ -89,7 +89,7 @@ impl Parsable for GameSave {
 
         // parse cube data
         let mut cubes_h = Vec::<EntityHeader>::with_capacity(cube_count as usize);
-        let mut cubes_e = Vec::<Box<dyn SerializedEntityDescriptor>>::with_capacity(cube_count as usize);
+        let mut cubes_e = Vec::<Box<dyn Block>>::with_capacity(cube_count as usize);
         for _i in 0..cube_count {
             let header = EntityHeader::parse(data)?;
             let hash = header.hash;
diff --git a/tests/techblox_parsing.rs b/tests/techblox_parsing.rs
index 09de5ad..1494aca 100644
--- a/tests/techblox_parsing.rs
+++ b/tests/techblox_parsing.rs
@@ -6,6 +6,8 @@ use libfj::techblox::{SerializedEntityDescriptor, Parsable, blocks, EntityHeader
 use std::io::{Read, Seek};
 #[cfg(feature = "techblox")]
 use std::fs::{File, OpenOptions};
+#[cfg(feature = "techblox")]
+use std::convert::AsRef;
 
 #[cfg(feature = "techblox")]
 const GAMESAVE_PATH: &str = "tests/GameSave.Techblox";
@@ -184,6 +186,10 @@ fn techblox_gamesave_parse_all() -> Result<(), ()> {
     for i in 0..(gs.group_len as usize) {
         assert_eq!(gs.group_headers[i].component_count, techblox::BlockGroupEntity::serialized_components());
         assert_eq!(gs.group_headers[i].hash, gs.cube_groups[i].hash_name());
+        /*let pos = format!("({}, {}, {})", gs.cube_groups[i].block_group_transform.block_group_grid_position.x, gs.cube_groups[i].block_group_transform.block_group_grid_position.y, gs.cube_groups[i].block_group_transform.block_group_grid_position.z);
+        let rot = format!("({}, {}, {}, {})", gs.cube_groups[i].block_group_transform.block_group_grid_rotation.value.x, gs.cube_groups[i].block_group_transform.block_group_grid_rotation.value.y, gs.cube_groups[i].block_group_transform.block_group_grid_rotation.value.z,
+        gs.cube_groups[i].block_group_transform.block_group_grid_rotation.value.w);
+        println!("block id: {}, position: {}, rotation: {}", gs.cube_groups[i].saved_block_group_id.saved_block_group_id, pos, rot);*/
     }
     for i in 1..(gs.cube_len as usize) {
         //assert_eq!(gs.cube_headers[i-1].hash, gs.cube_headers[i].hash);
@@ -221,3 +227,29 @@ fn techblox_gamesave_parse_all() -> Result<(), ()> {
     assert_eq!(in_file.stream_position().unwrap(), out_file.stream_position().unwrap());
     Ok(())
 }
+
+#[cfg(feature = "techblox")]
+#[test]
+fn techblox_gamesave_block_groups() -> Result<(), ()> {
+    let mut in_file = File::open(GAMESAVE_PATH_ALL).map_err(|_| ())?;
+    let mut buf = Vec::new();
+    in_file.read_to_end(&mut buf).map_err(|_| ())?;
+    let gs = techblox::GameSave::parse(&mut buf.as_slice()).map_err(|_| ())?;
+
+    for block_trait in &gs.cube_entities {
+        let block: &blocks::BlockEntity = block_trait.as_ref().as_ref();
+        //println!("Block @ ({}, {}, {})", block.pos_component.position.x, block.pos_component.position.y, block.pos_component.position.z);
+        assert!(is_in_block_groups(block.group_component.current_block_group, &gs.cube_groups));
+    }
+    Ok(())
+}
+
+#[cfg(feature = "techblox")]
+fn is_in_block_groups(id: i32, block_groups: &Vec<techblox::BlockGroupEntity>) -> bool {
+    for bg in block_groups {
+        if bg.saved_block_group_id.saved_block_group_id == id {
+            return true;
+        }
+    }
+    false
+}