diff --git a/src/object.c b/src/object.c
index 16a9af9..9bbbcbe 100644
--- a/src/object.c
+++ b/src/object.c
@@ -17,6 +17,12 @@
 #define printf(...) APP_LOG(APP_LOG_LEVEL_DEBUG, __VA_ARGS__)
 #endif
 
+#define FOR_POINTER_IN_LIST(_list) \
+    for(Object *_element = _list->list; \
+            _element != NULL;\
+            _element = _element->forward)
+#define POINTER _element
+
 /**
  * Returns the length of a given list Object
  * @param listObj The list to get the length of
@@ -27,15 +33,16 @@ int listLength(const Object *listObj)
     if(!listObj || listObj->type != TYPE_LIST)
         return -1;
 
-    Object *march = listObj->list;
     int len = 0;
-    while(march) {
-        march = march->forward;
+    FOR_POINTER_IN_LIST(listObj) {
         len++;
     }
     return len;
 }
 
+Object len(Object obj1, Object ignore)
+    { return numberObject(listLength(&obj1)); }
+
 /**
  * Returns a pointer to the Object at the given index in a given list
  * @param listObj The list to fetch an Object from
@@ -296,11 +303,9 @@ void printObj(const Object *obj)
 void _printList(const Object *list, int newline)
 {
     printf("(");
-    const Object *tail = list->list;
-    while(tail != NULL) {
+    FOR_POINTER_IN_LIST(list) {
         printf(" ");
-        _printObj(tail, 0);
-        tail = tail->forward;
+        _printObj(POINTER, 0);
     }
     printf(" )");
 
@@ -326,6 +331,7 @@ void cleanObject(Object *target)
     } else if(t == TYPE_LIST) {
         deleteList(target);
     }
+    target->forward = NULL;
 }
 
 void printAndClean(Object *target)
@@ -335,7 +341,7 @@ void printAndClean(Object *target)
 }
 
 // Frees all objects in a list
-void deleteList(const Object *dest)
+void deleteList(Object *dest)
 {
     if(!dest)
         return;
@@ -352,6 +358,7 @@ void deleteList(const Object *dest)
         cleanObject(prevMarch);
         free(prevMarch);
     }
+    dest->list = NULL;
 }
 
 /**
@@ -365,10 +372,8 @@ void copyList(Object *dest, const Object *src)
         return;
 
     deleteList(dest);
-    const Object *march = src->list;
-    while(march != NULL) {
-        nf_addToList(dest, *march);
-        march = march->forward;
+    FOR_POINTER_IN_LIST(src) {
+        nf_addToList(dest, *POINTER);
     }
 }
 
diff --git a/src/object.h b/src/object.h
index a3630b6..d485d27 100644
--- a/src/object.h
+++ b/src/object.h
@@ -10,6 +10,7 @@ enum errorCode {
     BAD_LIST_OF_SYMBOL_STRINGS,
     TYPE_LIST_NOT_CAUGHT,
     NULL_ENV,
+    EMPTY_ENV,
     BUILT_IN_NOT_FOUND,
     NULL_PARSE,
     NULL_LAMBDA_LIST,
@@ -26,6 +27,7 @@ static const char *errorText[] = {
     "BAD_LIST_OF_SYMBOL_STRINGS",
     "TYPE_LIST_NOT_CAUGHT",
     "NULL_ENV",
+    "EMPTY_ENV",
     "BUILT_IN_NOT_FOUND",
     "NULL_PARSE",
     "NULL_LAMBDA_LIST",
@@ -84,7 +86,7 @@ Object *tail(const Object *listObj);
 void insertIntoList(Object *dest, unsigned ind, const Object src);
 void replaceListing(Object *list, int i, const Object src);
 void nf_addToList(Object *dest, Object src);
-void deleteList(const Object *dest);
+void deleteList(Object *dest);
 
 int listLength(const Object *listObj);
 Object *itemAt(const Object *listObj, int n);
@@ -104,4 +106,7 @@ Object numberObject(int num);
 Object errorObject(enum errorCode err);
 Object constructLambda(const Object *params, const Object *body);
 
+// Object version of listLength()
+Object len(Object obj1, Object ignore);
+
 #endif
diff --git a/src/pebblisp.c b/src/pebblisp.c
index 8551dc9..a35e172 100644
--- a/src/pebblisp.c
+++ b/src/pebblisp.c
@@ -34,16 +34,23 @@ Object fetchFromEnvironment(const char *name, struct Environment *env)
     if(!env)
         return errorObject(NULL_ENV);
 
-    printd("Fetching '%s' from env\n", name);
+    if(env->size == 0)
+        return errorObject(EMPTY_ENV);
+
+    printf("Fetching '%s' from env\n", name);
     // printEnv(env);
     for(int i = 0; i < env->size; i++) {
+        printf("Try %d\n", i);
+        if(env->strings[i] == NULL)
+            break;
         if(strcmp(name, env->strings[i]) == 0) {
             return env->objects[i];
         }
     }
 
-    printd("Trying outer\n");
+    printf("Trying outer %p\n", env->outer);
     if(env->outer) {
+        printEnv(env->outer);
         return fetchFromEnvironment(name, env->outer);
     }
 
@@ -121,15 +128,15 @@ Object evalDefArgs(const Object *arg_forms, struct Environment *env)
 
 Object evalIfArgs(const Object *arg_forms, struct Environment *env)
 {
-    printf("eval(arg_forms):\n  ");
+    printd("eval(arg_forms):\n  ");
     Object o = eval(arg_forms, env);
-    printObj(&o);
-    printf("eval(arg_forms->forward):\n  ");
+    debugObj(&o);
+    printd("eval(arg_forms->forward):\n  ");
     o = eval(arg_forms->forward, env);
-    printObj(&o);
-    printf("eval(arg_forms->forward->forward):\n  ");
+    debugObj(&o);
+    printd("eval(arg_forms->forward->forward):\n  ");
     o = eval(arg_forms->forward->forward, env);
-    printObj(&o);
+    debugObj(&o);
     return eval(arg_forms, env).number? 
             eval(arg_forms->forward, env) : 
             eval(arg_forms->forward->forward, env);
@@ -177,26 +184,30 @@ struct Environment envForLambda(const Object *params, const Object *arg_forms,
     printd("envForLambda()\n");
     debugObj(arg_forms);
 
-    int length = listLength(params);
+    int paramCount = listLength(params);
 
     struct Environment env = {
         .outer = outer,
         .strings = NULL,
         .objects = NULL,
-        .size = length
+        .size = paramCount
     };
 
-    if(length == 0)
+    if(paramCount == 0)
         return env;
 
-    env.strings = calloc(sizeof(char*), length + 1);
-    env.objects = malloc(sizeof(Object) * length + 1);
+    env.strings = calloc(sizeof(char*), paramCount + 1);
+    env.objects = malloc(sizeof(Object) * paramCount + 1);
 
-    const Object *o = arg_forms;
-    for(int i = 0; i < length; i++) {
-        const char *n = itemAt(params, i)->name;
-        addToEnv(&env, n, eval(o, outer)); // Could use eval_forms?
-        o = o->forward;
+    const Object *march = arg_forms;
+    printf("Param count: %d\n", paramCount);
+    for(int i = 0; i < paramCount; i++) {
+        const char *newObjName = itemAt(params, i)->name;
+        const Object newEnvObj = eval(march, outer);
+        printf("Adding new object '%s' to lambda env: ", newObjName);
+        printObj(&newEnvObj);
+        addToEnv(&env, newObjName, newEnvObj); // Could use eval_forms?
+        march = march->forward;
     }
 
     return env;
@@ -208,6 +219,7 @@ Object evalBuiltIns(const Object *first, const Object *rest,
     if(strcmp(first->name, "def") == 0) {
         return evalDefArgs(rest, env);
     } else if(strcmp(first->name, "if") == 0) {
+        // Seems `rest` is the next *input*, not the next list item
         return evalIfArgs(rest, env);
     } else if(strcmp(first->name, "fn") == 0) {
         return evalLambdaArgs(rest);
@@ -226,6 +238,8 @@ void eval_forms(Object *destList, const Object *src, struct Environment *env)
     }
 }
 
+static int depth = 0;
+
 Object eval(const Object *obj, struct Environment *env)
 {
     printd("eval():\n");
@@ -236,7 +250,13 @@ Object eval(const Object *obj, struct Environment *env)
             return *obj; // Return as is
 
         case TYPE_SYMBOL:
-            return fetchFromEnvironment(obj->name, env);
+        {
+            depth++;
+            printf("depth: %d\n", depth);
+            const Object oi = fetchFromEnvironment(obj->name, env);
+            depth--;
+            return oi;
+        }
 
         case TYPE_LIST:
         {
@@ -310,11 +330,15 @@ void addToEnv(struct Environment *env, const char *name, const Object obj)
             env->strings[i] = calloc(sizeof(char), strlen(name) + 1);
             strncpy(env->strings[i], name, strlen(name));
             env->objects[i] = obj;
+            // if(obj.type == TYPE_LIST)
+            //     copyList(&env->objects[i], &obj);
             return;
         }
         if(strcmp(env->strings[i], name) == 0) {
             cleanObject(&env->objects[i]);
             env->objects[i] = obj;
+            // if(obj.type == TYPE_LIST)
+            //     copyList(&env->objects[i], &obj);
             return;
         }
     }
@@ -427,6 +451,7 @@ struct Environment defaultEnv() {
     addFunc("=", &equ, &e);
     addFunc(">", &gth, &e);
     addFunc("<", &lth, &e);
+    addFunc("len", &len, &e);
 
     return e;
 }