diff --git a/app.cpp b/app.cpp
index 4a77615..025d3e8 100644
--- a/app.cpp
+++ b/app.cpp
@@ -229,8 +229,9 @@ int day3_main() {
 }
 
 int day4_main() {
-    Arena arena = createArena(Megabytes(16));
-    list<char> file = readEntireFile(&arena, strlit("./day-4-input"));
+    Arena mainArena = createArena(Megabytes(16));
+    Arena *arena = &mainArena;
+    list<char> file = readEntireFile(arena, strlit("./day-4-input"));
 
     int fileReadIndex = 0;
     int lines = 0;
@@ -251,23 +252,24 @@ int day4_main() {
         fileReadIndex += lineLength + 1;
     }
 
-    list<char> fileStripped = PushList(&arena, char, file.length - lines);
-    for (size_t i = 0; i < file.length; i++) {
-        if (file.data[i] != '\n') {
-            appendList(&fileStripped, (char)file.data[i]);
-        }
-    }
-
     string xmas = strlit("XMAS");
-    int c = 0;
     int count = 0;
-    for (int c = 0; c < fileStripped.length; c++) {
-        string segment = strSlice(fileStripped.data, c, c+xmas.len);
-        const char *print = cstring(&arena, segment);
-        printf("%s\n", print);
-        if (strEql(segment, xmas)) {
-            c += xmas.len;
-            count++;
+    for (int c = 0; c < file.length; c++) {
+        string strings[] = {
+            //forwards 
+            strSlice(file.data, c, c+xmas.len),
+            //down 
+            strSlice(file.data, c, c+xmas.len),
+            //forwardsReverse 
+            strReverse(arena, strSlice(file.data, c, c+xmas.len)),
+            //downReverse 
+            strReverse(arena, strSlice(file.data, c, c+xmas.len)),
+        };
+        for (size_t i = 0; i < ArrayCount(strings); i++) {
+            if (strEql(strings[i], xmas)) {
+                c += xmas.len;
+                count++;
+            }
         }
     }
 
diff --git a/build b/build
index 984ffe3..41f7456 100755
--- a/build
+++ b/build
@@ -1,3 +1,3 @@
 #!/bin/bash
 
-clang ./app.cpp -o ./target/app
+gcc -g -g3 ./app.cpp -o ./target/app
diff --git a/core.hpp b/core.hpp
index a9cd613..b456c64 100644
--- a/core.hpp
+++ b/core.hpp
@@ -42,10 +42,11 @@ struct Arena {
     size_t head;
 };
 
-void *pushSize(Arena *arena, size_t size) {
-    if (arena->capacity - arena->head >= size) {
-        arena->head += size;
-        return (char *)arena->memory + arena->head + size;
+void *pushSize(Arena *arena, size_t bytes) {
+    if (arena->capacity - arena->head >= bytes) {
+        void *ptr = (char *)arena->memory + arena->head;
+        arena->head += bytes;
+        return ptr;
     }
     return 0;
 }
@@ -88,6 +89,9 @@ void zeroList(list<T> *list) {
     memset(list->data, 0, list->capacity * sizeof(T));
 }
 
+#define foreach(it, list, type) for (size_t __i = 0; __i < list.length; __i++) { type it = list.data[__i];
+#define foreach_end() }
+
 // ### Strings ###
 #define strlit(lit) ((string){(char *)(lit), sizeof(lit) - 1})
 
@@ -96,16 +100,18 @@ struct string {
     size_t len;
 };
 
+#define PushString(arena, length) ((string){ (char *)pushSize(arena, length), (length) })
+
 const char *cstring(Arena *arena, list<char> buf) {
     char *arr = PushArray(arena, char, buf.length + 1);
-    memcpy(arr, buf.data, sizeof(char) * buf.length);
+    memmove(arr, buf.data, buf.length);
     arr[buf.length] = '\0';
     return arr;
 }
 
 const char *cstring(Arena *arena, string str) {
     char *arr = PushArray(arena, char, str.len + 1);
-    memcpy(arr, str.str, str.len * sizeof(char));
+    memmove(arr, str.str, str.len);
     arr[str.len] = '\0';
     return arr;
 }
@@ -122,6 +128,18 @@ bool strEql(string s1, string s2) {
     return true;
 }
 
+string strReverse(Arena *arena, string str) {
+    string reversed = PushString(arena, str.len);
+    for (
+        int mainIndex = str.len - 1, reversedIndex = 0; 
+        mainIndex < str.len; 
+        mainIndex--, reversedIndex++
+    ) {
+        reversed.str[reversedIndex] = str.str[mainIndex];
+    }
+    return reversed;
+}
+
 string strSlice(char *data, size_t start, size_t stop) {
     return {
         data + start,