diff --git a/src/interpreter.c b/src/interpreter.c
index ed5c8fd..273d985 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -1,71 +1,22 @@
-#include "interpreter.h"
-#include "program.h"
+#include "types.h"
 
 #include <stddef.h>
-#include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-static void loop_end(Program* program) {
-    uint32_t count = 1;
+void interpret(Program* program) {
+    Stack tape_stack;
+    stack_init(&tape_stack, sizeof(void*));
+
+    Tape* tape = malloc(sizeof(Tape));
+    tape_init(tape, sizeof(void*));
+
+    stack_push(&tape_stack, tape);
+    
     Symbol s;
-
-    while (true) {
-        program_next(program, &s);
-        if (s == StartLoop) {
-            count++;
-        } else if (s == EndLoop) {
-            count--;
-        } else if (s == Eof) {
-            return;
-        }
-
-        if (count == 0) return;
-    }
-}
-
-static void loop_start(Program* program) {
-    uint32_t count = 1;
-    Symbol s;
-
-    program_last(program, &s);
-    while (true) {
-        program_last(program, &s);
-        if (s == StartLoop) {
-            count--;
-        } else if (s == EndLoop) {
-            count++;
-        } else if (s == Eof) {
-            return;
-        }
-
-        if (count == 0) {
-            return;
-        };
-    }
-}
-
-static void recurse_program(Program* program, Tape* tape) {
-    Symbol s;
-
 next:
-    program_next(program, &s);
-
-    // printf("[");
-    // for(uint32_t i = 0; i < tape->len; i++) {
-    //     printf("0x%02x ", tape->data[i]);
-    // }
-    // printf("\b]\n ");
-    // for(uint32_t i = 0; i < tape->len; i++) {
-    //     if (i == tape->index) {
-    //         printf("  ^  ");
-    //     } else {
-    //         printf("     ");
-    //     }
-    // }
-    // printf(" \ + tape->indexn");
-
+    program_get(program, &s);
+    
     switch (s) {
         case MoveLeft:
             tape_left(tape);
@@ -74,77 +25,72 @@ next:
             tape_right(tape);
             break;
         case Increment:
-            tape_set(tape, tape_get(tape) + 1);
+            tape_increment(tape);
             break;
         case Decrement:
-            tape_set(tape, tape_get(tape) - 1);
+            tape_decrement(tape);
             break;
         case StartLoop:
-            if (tape_get(tape) == 0)
-                loop_end(program);
+            if (tape_get(tape) == 0) {
+                program_seek(program, program_get_jump(program));
+            }
             break;
         case EndLoop:
-            if (tape_get(tape) != 0)
-                loop_start(program);
+            if (tape_get(tape) != 0) {
+                program_seek(program, program_get_jump(program));
+            }
             break;
         case PutChar: {
             printf("%c", tape_get(tape));
             break;
         }
         case GetChar: {
-            uint8_t c = (uint8_t) getchar();
-            tape_set(tape, c);
+            tape_set(tape, getchar());
             break;
         }
         case Allocate: {
-            uint8_t len = tape_get(tape);
             Tape* new = malloc(sizeof(Tape));
-            tape_init(len, new);
-            void* ptr = (void*) tape_ptr(tape);
-            memcpy(ptr, &new, sizeof(Tape*));
+            tape_init(new, tape_get(tape));
+            memcpy(tape_ptr(tape), &new, sizeof(Tape*));
             break;
         }
         case Free: {
             Tape* old;
-            void* ptr = (void*) tape_ptr(tape);
-            memcpy(&old, ptr, sizeof(Tape*));
-            memset(ptr, 0, sizeof(Tape*));
+            memcpy(&old, tape_ptr(tape), sizeof(Tape*));
             tape_free(old);
             free(old);
             break;
         }
         case EnterTape: {
-            Tape* cur;
-            void* ptr = (void*) tape_ptr(tape);
-            memcpy(&cur, ptr, sizeof(Tape*));
-            recurse_program(program, cur);
+            memcpy(&tape, tape_ptr(tape), sizeof(Tape*));
+            stack_push(&tape_stack, tape);
+            break;
+        }
+        case LeaveTape: {
+            tape = stack_pop(&tape_stack);
+            if (tape == NULL) goto end;
             break;
         }
         case GetString: {
-            uint8_t len = tape_get(tape);
-            void* ptr = (void*) tape_ptr(tape);
-            fgets(ptr, len, stdin);
+            fgets((char*) tape_ptr(tape), tape_get(tape), stdin);
             break;
         }
         case PutString: {
-            char* ptr = (char*) tape_ptr(tape);
-            printf("%s", ptr);
+            printf("%s", (char*) tape_ptr(tape));
             break;
         }
         case Clear:
             printf("\033c");
             break;
-        case LeaveTape:
         case Eof:
-            return;
+            goto end;
     }
 
+    program_next(program);
     goto next;
-}
+end:
+    tape_free(tape);
+    free(tape);
 
-void run_program(Program* program) {
-    Tape tape;
-    tape_init(sizeof(void*), &tape);
-    recurse_program(program, &tape);
-    tape_free(&tape);
+    stack_free(&tape_stack);
 }
diff --git a/src/interpreter.h b/src/interpreter.h
deleted file mode 100644
index b7c3e2a..0000000
--- a/src/interpreter.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-
-#include "program.h"
-
-void run_program(Program* program);
diff --git a/src/main.c b/src/main.c
index 20134cd..c51a88f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,10 +1,7 @@
-#include "program.h"
-#include "interpreter.h"
+#include "types.h"
 
-#include <stdio.h>
 #include <stdlib.h>
 #include <stdbool.h>
-#include <stdint.h>
 #include <string.h>
 #include <errno.h>
 
@@ -42,8 +39,8 @@ int main(int argc, char** argv) {
     }
 
     Program program;
-    program_init(file, &program);
-    run_program(&program);
+    program_init(&program, file);
+    interpret(&program);
     program_free(&program);
 
     return EXIT_SUCCESS;
diff --git a/src/program.c b/src/program.c
index 1d94da3..0fac9d5 100644
--- a/src/program.c
+++ b/src/program.c
@@ -1,10 +1,9 @@
-#include "program.h"
+#include "types.h"
 
-#include <stdio.h>
 #include <stdlib.h>
-#include <stdint.h>
 #include <string.h>
 #include <errno.h>
+#include <stdbool.h>
 
 static char next_char(FILE* file) {
     char c;
@@ -65,89 +64,69 @@ retest:
     }
 }
 
-void program_init(FILE* file, Program* program) {
+void program_init(Program* program, FILE* file) {
     uint32_t capacity = 8;
 
-    program->data = malloc(capacity * sizeof(Symbol));
+    program->data = malloc(capacity * sizeof(struct instruction));
     program->len = 0;
     program->index = 0;
 
+    Stack stack;
+    stack_init(&stack, 8);
+
     Symbol s;
     while(true) {
         s = next_symbol(file);
         
         if (program->len == capacity) {
             capacity *= 2;
-            program->data = realloc(program->data, capacity * sizeof(Symbol));
+            program->data = realloc(program->data, capacity * sizeof(struct instruction));
+        }
+
+        program->data[program->len].s = s;
+        program->data[program->len].j = 0;
+
+        if (s == StartLoop) {
+            stack_pushi(&stack, program->len);
+        } else if (s == EndLoop) {
+            uint32_t i = stack_popi(&stack);
+            program->data[program->len].j = i;
+            if (i != 0 || program->data[i].j == 0) {
+                program->data[i].j = program->len;
+            }
         }
 
-        program->data[program->len] = s;
         program->len++;
 
         if (s == Eof) break;
     }
-
+    stack_free(&stack);
     fclose(file);
 }
 
-void program_peek(Program* program, Symbol* symbol) {
-    *symbol = program->data[program->index];
-}
-
-void program_next(Program* program, Symbol* symbol) {
+void program_get(Program* program, Symbol* symbol) {
     if (program->index >= program->len) {
         *symbol = Eof;
         return;
     }
-    program_peek(program, symbol);
+    *symbol = program->data[program->index].s;
+}
+
+uint32_t program_get_jump(Program* program) {
+    if (program->index >= program->len) {
+        return 0;
+    }
+    return program->data[program->index].j;
+}
+
+void program_next(Program* program) {
     program->index++;
 }
 
-void program_last(Program* program, Symbol* symbol) {
-    if (program->index < 1) {
-        *symbol = Eof;
-        return;
-    }
-    program->index--;
-    program_peek(program, symbol);
+void program_seek(Program* program, uint32_t index) {
+    program->index = index;
 }
 
 void program_free(Program* program) {
     free(program->data);
 }
-
-void tape_init(uint32_t len, Tape* tape) {
-    tape->len = len;
-    tape->data = malloc(len);
-    tape->index = 0;
-    memset(tape->data, 0, len);
-}
-
-void tape_left(Tape* tape) {
-    if (tape->index == 0) {
-        tape->index = tape->len - 1;
-    } else {
-        tape->index--;
-    }
-}
-
-void tape_right(Tape* tape) {
-    tape->index++;
-    tape->index %= tape->len;
-}
-
-uint8_t tape_get(Tape* tape) {
-    return tape->data[tape->index];
-}
-
-void tape_set(Tape* tape, uint8_t value) {
-    tape->data[tape->index] = value;
-}
-
-uint8_t* tape_ptr(Tape* tape) {
-    return tape->data + tape->index;
-}
-
-void tape_free(Tape* tape) {
-    free(tape->data);
-}
diff --git a/src/program.h b/src/program.h
deleted file mode 100644
index ea29b6c..0000000
--- a/src/program.h
+++ /dev/null
@@ -1,50 +0,0 @@
-#pragma once
-
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdio.h>
-
-typedef enum {
-    MoveLeft,
-    MoveRight,
-    Increment,
-    Decrement,
-    StartLoop,
-    EndLoop,
-    PutChar,
-    GetChar,
-    Allocate,
-    Free,
-    EnterTape,
-    LeaveTape,
-    PutString,
-    GetString,
-    Clear,
-    Eof
-} Symbol;
-
-typedef struct {
-    uint32_t len;
-    uint32_t index;
-    Symbol* data;
-} Program;
-
-void program_init(FILE* file, Program* program);
-void program_peek(Program* program, Symbol* symbol);
-void program_next(Program* program, Symbol* symbol);
-void program_last(Program* program, Symbol* symbol);
-void program_free(Program* program);
-
-typedef struct {
-    uint32_t len;
-    uint32_t index;
-    uint8_t* data;
-} Tape;
-
-void tape_init(uint32_t len, Tape* tape);
-void tape_left(Tape* tape);
-void tape_right(Tape* tape);
-uint8_t tape_get(Tape* tape);
-void tape_set(Tape* tape, uint8_t value);
-uint8_t* tape_ptr(Tape* tape);
-void tape_free(Tape* tape);
diff --git a/src/stack.c b/src/stack.c
new file mode 100644
index 0000000..3491581
--- /dev/null
+++ b/src/stack.c
@@ -0,0 +1,47 @@
+#include "types.h"
+
+#include <stdlib.h>
+
+void stack_init(Stack* stack, uint32_t len) {
+    stack->index = 0;
+    stack->len = len;
+    stack->data = malloc(stack->len * sizeof(union stored));
+}
+
+void stack_push(Stack* stack, void* value) {
+    if (stack->index == stack->len) {
+        stack->len *= 2;
+        stack->data = realloc(stack->data, stack->len * sizeof(union stored));
+    }
+    stack->data[stack->index].p = value;
+    stack->index++;
+}
+
+void* stack_pop(Stack* stack) {
+    if (stack->index == 0) {
+        return NULL;
+    }
+    stack->index--;
+    return stack->data[stack->index].p;
+}
+
+void stack_pushi(Stack* stack, uint32_t value) {
+    if (stack->index == stack->len) {
+        stack->len *= 2;
+        stack->data = realloc(stack->data, stack->len * sizeof(union stored));
+    }
+    stack->data[stack->index].i = value;
+    stack->index++;
+}
+
+uint32_t stack_popi(Stack* stack) {
+    if (stack->index == 0) {
+        return 0;
+    }
+    stack->index--;
+    return stack->data[stack->index].i;
+}
+
+void stack_free(Stack* stack) {
+    free(stack->data);
+}
diff --git a/src/tape.c b/src/tape.c
new file mode 100644
index 0000000..8718cfd
--- /dev/null
+++ b/src/tape.c
@@ -0,0 +1,44 @@
+#include "types.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+void tape_init(Tape* tape, uint8_t len) {
+    tape->index = 0;
+    tape->len = len;
+    tape->data = malloc(tape->len);
+    memset(tape->data, 0, len);
+}
+
+void tape_free(Tape* tape) {
+    free(tape->data);
+}
+
+void tape_left(Tape* tape) {
+    tape->index--;
+}
+
+void tape_right(Tape* tape) {
+    tape->index++;
+}
+
+void tape_increment(Tape* tape) {
+    tape->data[tape->index]++;
+}
+
+void tape_decrement(Tape* tape) {
+    tape->data[tape->index]--;
+}
+
+uint8_t tape_get(Tape* tape) {
+    return tape->data[tape->index];
+}
+
+void tape_set(Tape* tape, uint8_t value) {
+    tape->data[tape->index] = value;
+}
+
+void* tape_ptr(Tape* tape) {
+    return tape->data + tape->index;
+}
diff --git a/src/types.h b/src/types.h
new file mode 100644
index 0000000..413d313
--- /dev/null
+++ b/src/types.h
@@ -0,0 +1,73 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdio.h>
+
+typedef enum {
+    MoveLeft,
+    MoveRight,
+    Increment,
+    Decrement,
+    StartLoop,
+    EndLoop,
+    PutChar,
+    GetChar,
+    Allocate,
+    Free,
+    EnterTape,
+    LeaveTape,
+    PutString,
+    GetString,
+    Clear,
+    Eof
+} Symbol;
+
+typedef struct {
+    uint32_t len;
+    uint32_t index;
+    struct instruction {
+        Symbol s;
+        uint32_t j;
+    } * data;
+} Program;
+
+void program_init(Program* program, FILE* file);
+void program_get(Program* program, Symbol* symbol);
+uint32_t program_get_jump(Program* program);
+void program_next(Program* program);
+void program_seek(Program* program, uint32_t index);
+void program_free(Program* program);
+
+typedef struct {
+    uint32_t len;
+    uint32_t index;
+    union stored {
+        void* p;
+        uint32_t i;
+    } * data;
+} Stack;
+
+void stack_init(Stack* stack, uint32_t len);
+void stack_push(Stack* stack, void* value);
+void* stack_pop(Stack* stack);
+void stack_pushi(Stack* stack, uint32_t value);
+uint32_t stack_popi(Stack* stack);
+void stack_free(Stack* stack);
+
+typedef struct {
+    uint8_t len;
+    uint8_t index;
+    uint8_t* data;
+} Tape;
+
+void tape_init(Tape* tape, uint8_t len);
+void tape_free(Tape* tape);
+void tape_left(Tape* tape);
+void tape_right(Tape* tape);
+void tape_increment(Tape* tape);
+void tape_decrement(Tape* tape);
+uint8_t tape_get(Tape* tape);
+void tape_set(Tape* tape, uint8_t value);
+void* tape_ptr(Tape* tape);
+
+void interpret(Program* program);