diff --git a/du5/snake.c b/du5/snake.c
index 7038cdb..810947a 100644
--- a/du5/snake.c
+++ b/du5/snake.c
@@ -1,23 +1,57 @@
 #include "snake.h"
 #include <stdlib.h>
 
-struct snake* add_snake(struct snake* snake,int x,int y){
-    return NULL;
+struct snake* add_snake(struct snake* snake, int x, int y) {
+    struct snake* head = calloc(1, sizeof(struct snake));
+    if (head == NULL) {
+        return NULL; // Handle memory allocation failure
+    }
+    head->x = x;
+    head->y = y;
+    head->next = snake;
+    return head;
 }
 
-struct snake* remove_snake(struct snake* snake){
-    return NULL;
+struct snake* remove_snake(struct snake* snake) {
+    if (snake == NULL) {
+        return NULL;
+    }
+    if (snake->next == NULL) {
+        free(snake);
+        return NULL;
+    }
+
+    struct snake* this = snake;
+    struct snake* prev = NULL;
+    while (this->next != NULL) {
+        prev = this;
+        this = this->next;
+    }
+
+    free(this);
+    prev->next = NULL;
+    return snake;
 }
 
-void free_snake(struct snake* sn){
+void free_snake(struct snake* sn) {
+    if (sn == NULL) {
+        return;
+    }
+    free_snake(sn->next);
+    free(sn);
 }
 
-int is_snake(struct snake* snake,int x,int y){
+int is_snake(struct snake* snake, int x, int y) {
+    for (struct snake* this = snake; this != NULL; this = this->next) {
+        if (this->x == x && this->y == y) {
+            return 1;
+        }
+    }
     return 0;
 }
 
-int step_state(struct state* st){
-	int nx = (st->snake->x + st->sx);
+int step_state(struct state* st) {
+    int nx = (st->snake->x + st->sx);
     int ny = (st->snake->y + st->sy);
     return END_CONTINUE;
 }