diff --git a/gs_libs/gs_win32.cpp b/gs_libs/gs_win32.cpp
index dd55973..e2df025 100644
--- a/gs_libs/gs_win32.cpp
+++ b/gs_libs/gs_win32.cpp
@@ -83,20 +83,26 @@ Win32StringLength(char* String)
 }
 
 internal s32 
-Win32ConcatStrings(s32 ALen, char* A, s32 BLen, char* B, s32 DestLen, char* Dest)
+Win32ConcatStrings(s32 ALength, char* A, s32 BLength, char* B, s32 DestLength, char* Dest)
 {
     char* Dst = Dest;
     char* AAt = A;
-    for (s32 a = 0; a < ALen; a++)
+    int ALengthToCopy = ALength < DestLength ? ALength : DestLength;
+    for (s32 a = 0; a < ALength; a++)
     {
         *Dst++ = *AAt++;
     }
     char* BAt = B;
-    for (s32 b = 0; b < BLen; b++)
+    int DestLengthRemaining = DestLength - (Dst - Dest);
+    int BLengthToCopy = BLength < DestLengthRemaining ? BLength : DestLength;
+    for (s32 b = 0; b < BLengthToCopy; b++)
     {
         *Dst++ = *BAt++;
     }
-    return Dst - Dest;
+    int DestLengthOut = Dst - Dest;
+    int NullTermIndex = DestLengthOut < DestLength ? DestLengthOut : DestLength;
+    Dest[NullTermIndex] = 0;
+    return DestLengthOut;
 }
 
 ///
diff --git a/src/foldhaus_app.cpp b/src/foldhaus_app.cpp
index e3c996f..a62d462 100644
--- a/src/foldhaus_app.cpp
+++ b/src/foldhaus_app.cpp
@@ -341,13 +341,25 @@ UPDATE_AND_RENDER(UpdateAndRender)
         State->AnimationSystem.LastUpdatedFrame = CurrentFrame;
         r32 FrameTime = CurrentFrame * State->AnimationSystem.SecondsPerFrame;
         
+        u32 CurrentBlocksMax = State->AnimationSystem.LayersCount;
+        b8* CurrentBlocksFilled = PushArray(&State->Transient, b8, CurrentBlocksMax);
+        GSZeroArray(CurrentBlocksFilled, b8, CurrentBlocksMax);
+        animation_block* CurrentBlocks = PushArray(&State->Transient, animation_block, CurrentBlocksMax);
+        
         for (u32 i = 0; i < State->AnimationSystem.Blocks.Used; i++)
         {
             gs_list_entry<animation_block>* BlockEntry = State->AnimationSystem.Blocks.GetEntryAtIndex(i);
             if (EntryIsFree(BlockEntry)) { continue; }
             animation_block Block = BlockEntry->Value;
             if (CurrentFrame < Block.Range.Min || CurrentFrame > Block.Range.Max) { continue; }
-            
+            CurrentBlocksFilled[Block.Layer] = true;
+            CurrentBlocks[Block.Layer] = Block;
+        }
+        
+        for (s32 Layer = CurrentBlocksMax - 1; Layer >= 0; Layer--)
+        {
+            if (!CurrentBlocksFilled[Layer]) { continue; }
+            animation_block Block = CurrentBlocks[Layer];
             for (u32 j = 0; j < State->ActiveAssemblyIndecies.Used; j++)
             {
                 gs_list_handle AssemblyHandle = *State->ActiveAssemblyIndecies.GetElementAtIndex(j);
diff --git a/src/foldhaus_app.h b/src/foldhaus_app.h
index 822573c..840af74 100644
--- a/src/foldhaus_app.h
+++ b/src/foldhaus_app.h
@@ -151,12 +151,12 @@ TestPatternTwo(assembly* Assembly, r32 Time)
             }
             else
             {
-                Assembly->Colors[LED.Index] = {};
+                //Assembly->Colors[LED.Index] = {};
             }
         }
         else
         {
-            Assembly->Colors[LED.Index] = {};
+            //Assembly->Colors[LED.Index] = {};
         }
     }
 }
diff --git a/src/win32_foldhaus_dll.h b/src/win32_foldhaus_dll.h
index 13c78cb..01b6bea 100644
--- a/src/win32_foldhaus_dll.h
+++ b/src/win32_foldhaus_dll.h
@@ -14,13 +14,44 @@ struct win32_dll_refresh
     FILETIME LastWriteTime;
     HMODULE DLL;
     
-    b32 IsValid;
+    bool IsValid;
     
     char SourceDLLPath[MAX_PATH];
     char WorkingDLLPath[MAX_PATH];
     char LockFilePath[MAX_PATH];
 };
 
+internal int
+Win32DLLStringLength(char* String)
+{
+    char* At = String;
+    while (*At) { At++; };
+    return At - String;
+}
+
+internal int
+Win32DLLConcatStrings(int ALength, char* A, int BLength, char* B, int DestLength, char* Dest)
+{
+    char* Dst = Dest;
+    char* AAt = A;
+    int ALengthToCopy = ALength < DestLength ? ALength : DestLength;
+    for (s32 a = 0; a < ALength; a++)
+    {
+        *Dst++ = *AAt++;
+    }
+    char* BAt = B;
+    int DestLengthRemaining = DestLength - (Dst - Dest);
+    int BLengthToCopy = BLength < DestLengthRemaining ? BLength : DestLength;
+    for (s32 b = 0; b < BLengthToCopy; b++)
+    {
+        *Dst++ = *BAt++;
+    }
+    int DestLengthOut = Dst - Dest;
+    int NullTermIndex = DestLengthOut < DestLength ? DestLengthOut : DestLength;
+    Dest[NullTermIndex] = 0;
+    return DestLengthOut;
+}
+
 internal void
 GetApplicationPath(system_path* Result)
 {
@@ -81,15 +112,15 @@ InitializeDLLHotReloading(char* SourceDLLName,
     ExePath.Path = (char*)VirtualAlloc(NULL, ExePath.PathLength, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
     GetApplicationPath(&ExePath);
     
-    Win32ConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
-                       Win32StringLength(SourceDLLName), SourceDLLName,
-                       MAX_PATH, Result.SourceDLLPath);
-    Win32ConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
-                       Win32StringLength(WorkingDLLFileName), WorkingDLLFileName,
-                       MAX_PATH, Result.WorkingDLLPath);
-    Win32ConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
-                       Win32StringLength(LockFileName), LockFileName,
-                       MAX_PATH, Result.LockFilePath);
+    Win32DLLConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
+                          Win32DLLStringLength(SourceDLLName), SourceDLLName,
+                          MAX_PATH, Result.SourceDLLPath);
+    Win32DLLConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
+                          Win32DLLStringLength(WorkingDLLFileName), WorkingDLLFileName,
+                          MAX_PATH, Result.WorkingDLLPath);
+    Win32DLLConcatStrings(ExePath.IndexOfLastSlash, ExePath.Path,
+                          Win32DLLStringLength(LockFileName), LockFileName,
+                          MAX_PATH, Result.LockFilePath);
     
     Win32Free((u8*)ExePath.Path, ExePath.PathLength);
     return Result;
diff --git a/todo.txt b/todo.txt
index aaf9384..06de4c0 100644
--- a/todo.txt
+++ b/todo.txt
@@ -75,10 +75,15 @@ Ground Up Reengineering
     x zoom in and out
     - blending between animation
     - layers
-        - display more than one layer
-        - add/remove layers
+        x display more than one layer
+        x add/remove layers
         - layer masks by sculpture
-        - blend modes
+        - blend modes - create a copy of the led's per layer, handle blending outside of patterns
+    - interface for animation system
+        - add/remove layers
+        - select blend modes
+        - change which layer an animation is on
+        - 
     - setting start and end of timeline (how long is a loop)
     - clips can have parameters that drive them?