diff --git a/src/calc.c b/src/calc.c
index 7e502ec..514b383 100644
--- a/src/calc.c
+++ b/src/calc.c
@@ -190,11 +190,11 @@ void code_window_load(Window *window)
     window_stack_push(s_code_window, true);
 
     // If possible, load the previous code text
-    Object obj = parseEval("(def ad (fn (a) (* 3 a)))", &env);
+    // Object obj = parseEval("(def ad (fn (a) (* 3 a)))", &env);
     // Object obj2 = parseEval("(map ad (1 50 99))", &env);
     // printObj(&obj);
     // printObj(&obj2);
-    cleanObject(&obj);
+    // cleanObject(&obj);
     // cleanObject(&obj2);
     if(persist_exists(current_code)) {
         persist_read_string(current_code, mytext, SMAX_LENGTH);
diff --git a/src/object.c b/src/object.c
index 1924b10..b26e1dc 100644
--- a/src/object.c
+++ b/src/object.c
@@ -17,12 +17,6 @@
 #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
@@ -40,7 +34,7 @@ int listLength(const Object *listObj)
     return len;
 }
 
-Object len(Object obj1, Object ignore)
+Object len(Object obj1, Object o_ignore, struct Environment *e_ignore)
     { return numberObject(listLength(&obj1)); }
 
 /**
diff --git a/src/object.h b/src/object.h
index d485d27..cf2161e 100644
--- a/src/object.h
+++ b/src/object.h
@@ -5,6 +5,19 @@
 #define MAX_TOK_CNT 128 // 128
 #define MAX_ENV_ELM 15  // 50
 
+#define FOR_POINTER_IN_LIST(_list) \
+    for(Object *_element = _list->list; \
+            _element != NULL;\
+            _element = _element->forward)
+#define POINTER _element
+
+#define FOR_POINTERS_IN_LISTS(_list1, _list2) \
+    for(Object *_element = _list1->list, *_element2 = _list2->list; \
+            _element != NULL && _element2 != NULL; \
+            _element = _element->forward, _element2 = _element2->forward)
+#define P1 POINTER
+#define P2 _element2
+
 enum errorCode {
     MISMATCHED_PARENS,
     BAD_LIST_OF_SYMBOL_STRINGS,
@@ -18,7 +31,8 @@ enum errorCode {
     LAMBDA_ARGS_NOT_LIST,
     DID_NOT_FIND_SYMBOL,
     BAD_TYPE,
-    UNEXPECTED_FORM
+    UNEXPECTED_FORM,
+    LISTS_NOT_SAME_SIZE
 };
 
 //#ifdef STANDALONE
@@ -35,7 +49,8 @@ static const char *errorText[] = {
     "LAMBDA_ARGS_NOT_LIST",
     "DID_NOT_FIND_SYMBOL",
     "BAD_TYPE",
-    "UNEXPECTED_FORM"
+    "UNEXPECTED_FORM",
+    "LISTS_NOT_SAME_SIZE"
 };
 //#endif
 
@@ -54,6 +69,8 @@ typedef enum Type {
 typedef struct Object Object;
 struct Lambda;
 
+struct Environment;
+
 struct Object {
     Type type;
     Object *forward;
@@ -61,7 +78,7 @@ struct Object {
         int number;
         Object *list;
         char name[MAX_TOK_LEN];
-        Object (*func)(Object, Object);
+        Object (*func)(Object, Object, struct Environment *env);
         struct Lambda *lambda; // Maybe better as not a pointer?
         enum errorCode err;
     };
@@ -107,6 +124,6 @@ Object errorObject(enum errorCode err);
 Object constructLambda(const Object *params, const Object *body);
 
 // Object version of listLength()
-Object len(Object obj1, Object ignore);
+Object len(Object obj1, Object, struct Environment *);
 
 #endif
diff --git a/src/pebblisp.c b/src/pebblisp.c
index e875d25..7107b9f 100644
--- a/src/pebblisp.c
+++ b/src/pebblisp.c
@@ -118,7 +118,6 @@ Object evalDefArgs(const Object *arg_forms, struct Environment *env)
     const Object *first_form = arg_forms;
     const char *name = first_form->name;
 
-    // Immediately adding the function to the env might allow recursion?
     Object second_eval = eval(first_form->forward, env);
 
     addToEnv(env, name, second_eval);
@@ -210,7 +209,6 @@ 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);
@@ -252,7 +250,7 @@ Object eval(const Object *obj, struct Environment *env)
             Object *first_form = obj->list;
 
             { // Try to eval built-ins
-                Object built_in = 
+                const Object built_in =
                         evalBuiltIns(first_form, first_form->forward, env);
                 
                 // deleteList(obj); // Decreases indirectly lost memory, but fails on Pebble
@@ -269,7 +267,7 @@ Object eval(const Object *obj, struct Environment *env)
 
                 Object func_eval = rest[0];
                 for(int i = 1; i < length; i++) {
-                    func_eval = first_eval.func(func_eval, rest[i]);
+                    func_eval = first_eval.func(func_eval, rest[i], env);
                 }
                 // deleteList(obj); // Decreases indirectly lost memory, but fails on Pebble
                 return func_eval;
@@ -355,7 +353,7 @@ void printEnv(struct Environment *env)
     }
 }
 
-Object basicOp(Object *obj1, Object *obj2, const char op)
+Object _basicOp(const Object *obj1, const Object *obj2, const char op)
 {
     const int n1 = obj1->number;
     const int n2 = obj2->number;
@@ -381,9 +379,39 @@ Object basicOp(Object *obj1, Object *obj2, const char op)
     return *obj1;
 }
 
+Object basicOp(const Object *obj1, const Object *obj2, const char op,
+               struct Environment *env)
+{
+    int lists = (obj1->type == TYPE_LIST) + (obj2->type == TYPE_LIST);
+    if(lists == 0) {
+        return _basicOp(obj1, obj2, op);
+    } else if(lists == 1) { // Single operand is applied to each element in list
+        const Object *listObj = (obj1->type == TYPE_LIST)? obj1 : obj2;
+        const Object *singleObj = (obj1->type == TYPE_LIST)? obj2 : obj1;
+        Object newList = listObject();
+        FOR_POINTER_IN_LIST(listObj) {
+            Object adding = eval(POINTER, env);
+            nf_addToList(&newList, _basicOp(&adding, singleObj, op));
+        }
+        return newList;
+    } else { // 2 lists
+        if(listLength(obj1) == listLength(obj2)) {
+            Object newList = listObject();
+            FOR_POINTERS_IN_LISTS(obj1, obj2) {
+                Object ev1 = eval(P1, env);
+                Object ev2 = eval(P2, env);
+                nf_addToList(&newList, _basicOp(&ev1, &ev2, op));
+            }
+            return newList;
+        } else {
+            return errorObject(LISTS_NOT_SAME_SIZE);
+        }
+    }
+}
+
 #define bopf(_name, _char) \
-Object _name(Object obj1, Object obj2) \
-    { return basicOp(&obj1, &obj2, _char); }
+Object _name(Object obj1, Object obj2, struct Environment *env) \
+    { return basicOp(&obj1, &obj2, _char, env); }
 
 bopf(add, '+');
 bopf(sub, '-');
@@ -393,7 +421,7 @@ bopf(equ, '=');
 bopf(gth, '>');
 bopf(lth, '<');
 
-void addFunc(const char *name, Object (*func)(Object, Object), 
+void addFunc(const char *name, Object (*func)(Object, Object, struct Environment*),
                struct Environment *env)
 {
     Object o = newObject(TYPE_FUNC);
diff --git a/src/pebblisp.h b/src/pebblisp.h
index 1edf284..1ce513d 100644
--- a/src/pebblisp.h
+++ b/src/pebblisp.h
@@ -50,7 +50,6 @@ struct Environment envForLambda(const Object *params, const Object *arg_forms,
                                 struct Environment *outer);
 
 Result result(Object obj, struct Slice *slices);
-Object add(Object obj1, Object obj2);
 
 // Slices
 void copySlice(char * dest, struct Slice *src);
diff --git a/src/tokens.h b/src/tokens.h
index 03a2fe0..c73685b 100644
--- a/src/tokens.h
+++ b/src/tokens.h
@@ -2,6 +2,7 @@
 #define TOKENS_H
 
 #include "pebblisp.h"
+
 int isSingle(const char c);
 int isDigit(const char c);
 struct Slice *nf_tokenize(const char *input);