diff --git a/src/list b/src/list
new file mode 160000
index 0000000..23faa20
--- /dev/null
+++ b/src/list
@@ -0,0 +1 @@
+Subproject commit 23faa20d03b67d752e1f882f0832c941a942c75b
diff --git a/testline.c b/testline.c
new file mode 100644
index 0000000..fed75c0
--- /dev/null
+++ b/testline.c
@@ -0,0 +1,213 @@
+#include <stdio.h>
+#include <string.h>
+#include "src/list/src/list.h"
+
+/*
+typedef struct InfoState {
+  char* info;
+  int len;
+  int fullLines;
+  int Nlines;
+  int lastlinelen;
+  char *pos1, *pos2, *pos3;
+  list_t* wrap;
+} InfoState;
+
+void initInfoState(InfoState* st, char* text) {
+  st->info = text;
+  st->len = strlen(text);
+  st->fullLines = st->len / 15;
+  st->Nlines = (st->len + 14) / 15;
+  st->lastlinelen = st->len % 15;
+  st->pos1 = text;
+  st->pos2 = text;
+  st->pos3 = text;
+  st->wrap = list_new();
+  char* tmp = text;
+  //list_node_t *c = list_rpush(st->wrap, list_node_new("c"));
+}
+
+void lcd_blank_line() {
+  for (int i = 0; i < 15; ++i) {
+    lcd.print(' ');
+  }
+}
+
+void initInfoScreen(InfoState* st, char* text) {
+  initInfoState(st, text);
+  lcd.setCursor(0, 0);
+  if (*(st->pos1) == '\n' || *(st->pos1) == '\r') {
+    lcd_blank_line();
+    ++st->pos1;
+    ++st->pos2;
+  } else {
+    st->pos2 += lcd_print_line(st->pos1);
+  }
+  lcd.setCursor(0, 1);
+  if ((*(st->pos2) == '\n' || *(st->pos2) == '\r') && *(st->pos2 - 1) == *(st->pos2)) {
+    lcd_blank_line();
+  } else {
+    lcd_print_line(st->pos2);
+  }
+#ifdef DEBUG
+  //Serial.println(String("pos1: ") + st->pos1);
+  //Serial.println(String("pos2: ") + st->pos2);
+  Serial.println("init");
+  Serial.print(st->pos1-st->info);
+  Serial.println(String(" ")+(st->pos2-st->info));
+#endif
+}
+*/
+
+list_t* aux_gen_wrap_list(list_t* wrap, char* text) {
+  if (wrap == NULL) {
+    wrap = list_new();
+  }
+  char* curr = text;
+  int suf = 0;
+  list_node_t *node;
+  if (list_rpush(wrap, list_node_new(0)) == NULL) {
+    return NULL;
+  }
+  while (*curr != '\0') {
+    //printf("suf: %d\tpos: %d\n", suf, (unsigned int)(curr-text));
+    if (suf < 15) {
+      if (*curr != '\n' && *curr != '\r') {
+        ++suf;
+      } else {
+        if (list_rpush(wrap, list_node_new((unsigned int)(curr-text))) == NULL) {
+          return NULL;
+        }
+        suf = 0;
+      }
+    } else {
+      if (list_rpush(wrap, list_node_new((unsigned int)(curr-text))) == NULL) {
+        return NULL;
+      }
+      suf = (*curr != '\n' && *curr != '\r') ? 1 : 0;      
+    }
+    ++curr;
+  }
+  return wrap;
+}
+
+/*
+  Separate a substring that can be printed on one line, and return the 
+  original string position corresponding to the end of the substring.
+ */
+/*
+char* aux_sub_line(char* str, char substr[16]) {
+  int suf = 0;
+  char* curr = str;
+  memset(substr, 0, 16);
+  
+  while (*curr != '\0' && suf < 15) {
+    if (*curr != '\n' && *curr != '\r') {
+      substr[suf++] = *(curr++);
+      //++curr;
+    } else 
+    if (curr == str){ ++curr; } else 
+    {
+      break;
+    }
+  }
+  
+//#if !REFRESH
+  while (suf < 15) {
+    substr[suf++] = ' ';
+  }
+//#endif
+  return curr;
+}
+
+char* aux_sub_line_rev(char* str, char substr[16]) {
+  int suf = 0;
+  char* curr = str;
+  memset(substr, 0, 16);
+  
+  while (*curr != '\0' && suf < 15) {
+    if (*curr != '\n' && *curr != '\r') {
+      substr[suf++] = *(curr--);
+    } else 
+    if (curr == str){ --curr; } else 
+    {
+      break;
+    }
+  }
+  
+  {
+  int i = 0;
+  int j = suf - 1;
+  while (i < j) {
+      char temp = substr[i];
+      substr[i] = substr[j];
+      substr[j] = temp;
+      i++;
+      j--;
+  }
+  }
+  
+//#if !REFRESH
+  while (suf < 15) {
+    substr[suf++] = ' ';
+  }
+//#endif
+  return curr+1;
+}
+*/
+
+int main() {
+  char* cinfo = "Far far away, a\n\nbehind the word mountains, far from the countries Vokalia and Consonantia, there live the blind texts.";
+  
+  list_t *wrap = list_new();
+  wrap = aux_gen_wrap_list(wrap, cinfo);
+  
+  list_node_t *node;
+  list_iterator_t *it = list_iterator_new(wrap, LIST_HEAD);
+  
+  
+  while ((node = list_iterator_next(it))) {
+    printf("%d\n", (unsigned int)(node->val));
+  }
+  
+  /*
+  if ((node = list_iterator_next(it))) {
+    char* p = cinfo;
+    list_node_t *test;
+    while (*p != '\0') {
+      //printf("node->val: %d\n", node->val);
+      if (p - cinfo != node->val) {
+        printf("%c", *p);
+        //printf("%d %d\n", (unsigned int)(p - cinfo), (unsigned int)(node->val));
+      } else {
+        printf("|\n");
+        if (*p != '\n' && *p != '\r') {
+          printf("%c", *p);
+        }
+        if ((test = list_iterator_next(it))) {
+          node = test;
+        }
+      }
+      ++p;
+    }
+  } else {
+    printf("%s", cinfo);
+  }
+  */
+  /*
+  char line[16];
+  char* pos = aux_sub_line(cinfo, line);
+  printf("%d\n%s\n", pos-cinfo, line);
+  for (int i = 0; i < 4; ++i) {
+    pos = aux_sub_line(pos, line);
+    printf("%d\n%s\n", pos-cinfo, line);
+  }
+  for (int i = 0; i < 4; ++i) {
+    pos = aux_sub_line_rev(pos-1, line);
+    printf("%d\n%s\n", pos-cinfo, line);
+  }
+  */
+  list_iterator_destroy(it);
+  list_destroy(wrap);
+  return 0;
+}
\ No newline at end of file
diff --git a/testline.ino b/testline.ino
new file mode 100644
index 0000000..3984b6d
--- /dev/null
+++ b/testline.ino
@@ -0,0 +1,341 @@
+#include <stdint.h>
+#include <LiquidCrystal.h>
+#include "src/list/src/list.h"
+
+LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
+
+//#define REFRESH 1
+#define DEBUG
+
+uint8_t up_arrow[8]   = {0x04,0x0E,0x1F,0x1F,0x00,0x00,0x00,0x00};
+uint8_t down_arrow[8] = {0x00,0x00,0x00,0x1F,0x1F,0x0E,0x04,0x04};
+
+typedef struct InfoState {
+  char* info;
+  int len;
+  int fullLines;
+  int Nlines;
+  int lastlinelen;
+  char *pos1, *pos2, *pos3;
+  list_t *wrap;
+  list_iterator_t *it;
+} InfoState;
+
+void setup() {
+  Serial.begin(9600);
+  lcd.begin(16, 2);
+  lcd.createChar(0, up_arrow);
+  lcd.createChar(1, down_arrow);
+  lcd.setCursor(0, 0);
+  lcd.print("...............");
+  lcd.setCursor(0, 1);
+  lcd.print("...............");
+}
+
+void loop() {
+  char* cinfo = "Far far away, a\n\nbehind the word mountains, far from the countries Vokalia and Consonantia, there live the blind texts.";
+  //String info = "hello,`world!wwwwwwwwwwwwwwww";
+  InfoState st;
+  initInfoScreen(&st, cinfo);
+  
+#ifdef DEBUG
+  Serial.println(String("len: ") + st.len);
+#endif
+
+#ifdef DEBUG
+  Serial.println("down");
+#endif
+  for (int i = 0; i < 3; ++i) {
+    delay(1000);
+    scrollDown(&st);
+  }
+  
+#ifdef DEBUG
+  Serial.println("up");
+#endif
+  for (int i = 0; i < 5; ++i) {
+    delay(1000);
+    scrollUp(&st);
+  }
+  
+#ifdef DEBUG
+  Serial.println("down2");
+#endif
+  for (int i = 0; i < 3; ++i) {
+    delay(1000);
+    scrollDown(&st);
+  }
+  
+#ifdef DEBUG
+  Serial.println("up2");
+#endif
+  for (int i = 0; i < 5; ++i) {
+    delay(1000);
+    scrollUp(&st);
+  }
+
+  delay(3000);
+}
+
+list_t* aux_gen_wrap_list(list_t* wrap, char* text) {
+  if (wrap == NULL) {
+    wrap = list_new();
+  }
+  char* curr = text;
+  int suf = 0;
+  list_node_t *node;
+  if (list_rpush(wrap, list_node_new(0)) == NULL) {
+    return NULL;
+  }
+  while (*curr != '\0') {
+    //printf("suf: %d\tpos: %d\n", suf, (unsigned int)(curr-text));
+    if (suf < 15) {
+      if (*curr != '\n' && *curr != '\r') {
+        ++suf;
+      } else {
+        if (list_rpush(wrap, list_node_new((unsigned int)(curr-text))) == NULL) {
+          return NULL;
+        }
+        suf = 0;
+      }
+    } else {
+      if (list_rpush(wrap, list_node_new((unsigned int)(curr-text))) == NULL) {
+        return NULL;
+      }
+      suf = (*curr != '\n' && *curr != '\r') ? 1 : 0;      
+    }
+    ++curr;
+  }
+  if (list_rpush(wrap, list_node_new(strlen(text))) == NULL) {
+    return NULL;
+  }
+  return wrap;
+}
+
+void initInfoState(InfoState* st, char* text) {
+  st->info = text;
+  st->len = strlen(text);
+  st->fullLines = st->len / 15;
+  st->Nlines = (st->len + 14) / 15;
+  st->lastlinelen = st->len % 15;
+  st->pos1 = text;
+  st->pos2 = text;
+  st->pos3 = text;
+  st->wrap = list_new();
+  st->wrap = aux_gen_wrap_list(st->wrap, st->info);
+  st->it = list_iterator_new(st->wrap, LIST_HEAD);
+}
+
+void initInfoScreen(InfoState* st, char* text) {
+  initInfoState(st, text);
+  lcd.setCursor(0, 0);
+  
+  /*
+  if (*(st->pos1) == '\n' || *(st->pos1) == '\r') {
+    lcd_blank_line();
+    ++st->pos1;
+    ++st->pos2;
+  } else {
+    st->pos2 += lcd_print_line(st->pos1);
+  }
+  lcd.setCursor(0, 1);
+  if ((*(st->pos2) == '\n' || *(st->pos2) == '\r') && *(st->pos2 - 1) == *(st->pos2)) {
+    lcd_blank_line();
+  } else {
+    lcd_print_line(st->pos2);
+  }
+#ifdef DEBUG
+  //Serial.println(String("pos1: ") + st->pos1);
+  //Serial.println(String("pos2: ") + st->pos2);
+  Serial.println("init");
+  Serial.print(st->pos1-st->info);
+  Serial.println(String(" ")+(st->pos2-st->info));
+#endif
+  */
+}
+
+
+void scrollDown(InfoState* st) {
+  st->pos1 = st->pos2;
+  lcd.setCursor(0, 0);
+  if ((*(st->pos1) == '\n' || *(st->pos1) == '\r') && *(st->pos1 - 1) == *(st->pos1)) {
+    lcd_blank_line();
+    ++st->pos1;
+    ++st->pos2;
+  } else {
+    st->pos2 += lcd_print_line(st->pos1);
+  }
+  lcd.setCursor(0, 1);
+  if ((*(st->pos2) == '\n' || *(st->pos2) == '\r') && *(st->pos2 - 1) == *(st->pos2)) {
+    lcd_blank_line();
+  } else {
+    lcd_print_line(st->pos2);
+  }
+#ifdef DEBUG
+  //Serial.println(String("pos1: ") + st->pos1);
+  //Serial.println(String("pos2: ") + st->pos2);
+  Serial.print(st->pos1-st->info);
+  Serial.println(String(" ")+(st->pos2-st->info));
+#endif
+}
+
+void scrollUp(InfoState* st) {
+  if (st->pos1 > st->info) {
+    st->pos2 = st->pos1;
+    int i = 1;
+    int va = 1;
+    /*
+    int bound = min(st->pos1, 15);
+    Serial.println(String("bound: ")+bound);
+    while (i < bound) {
+      if (st->info[st->pos1-i] != '\n' && st->info[st->pos1-i] != '\r') {
+        ++i;
+      } else 
+      if (i == 1){ ++i; ++bound; } else 
+      {
+        break;
+      }
+    }
+    */
+    
+    /*
+    while (i < st->pos1-st->info && va < 15) {
+      if (st->info[st->pos1-i] != '\n' && st->info[st->pos1-i] != '\r') {
+        ++i;
+        ++va;
+      } else 
+      if (i == 1){ ++i; } else 
+      {
+        break;
+      }
+    }
+    
+    st->pos1 -= i;
+    */
+    bool is_blank = false;
+    while (st->pos1 > st->info && va <= 15) {
+      if (*(st->pos1) != '\n' && *(st->pos1) != '\r') {
+        ++i;
+        ++va;
+      } else if (*(st->pos1 - 1) == *(st->pos1)) {
+        is_blank = true;
+        --st->pos1;
+        break;
+      }
+      --st->pos1;
+    }
+    while (st->pos1 > st->info && (*(st->pos1) == '\n' || *(st->pos1) == '\r')) {
+      --st->pos1;
+    }
+    //st->pos1 -= i;
+    
+    lcd.setCursor(0, 0);
+    if (is_blank) {
+      lcd_blank_line();
+    } else {
+      lcd_print_line(st->pos1);
+    }
+    lcd.setCursor(0, 1);
+    if ((*(st->pos2) == '\n' || *(st->pos2) == '\r') && *(st->pos2 - 1) == *(st->pos2)) {
+      lcd_blank_line();
+    } else {
+      lcd_print_line(st->pos2);
+    }
+  }
+#ifdef DEBUG
+  //Serial.println(String("pos1: ") + st->pos1);
+  //Serial.println(String("pos2: ") + st->pos2);
+  Serial.print(st->pos1-st->info);
+  Serial.println(String(" ")+(st->pos2-st->info));
+#endif
+}
+
+int lcd_print_line(char* str) {
+  int i = 0;
+  int va = 0;
+  /*
+  int bound = min(strlen(str), 15);
+  while (i < bound) {
+    if (str[i] != '\n' && str[i] != '\r') {
+      lcd.print(str[i++]);
+    } else 
+    if (i == 0){ ++i; ++bound;} else 
+    {
+      break;
+    }
+  }
+  */
+  int slen = strlen(str);
+  while (i < slen && va < 15) {
+    if (str[i] != '\n' && str[i] != '\r') {
+      lcd.print(str[i++]);
+      ++va;
+    } else 
+    if (i == 0){ ++i; } else 
+    {
+      break;
+    }
+  }
+  
+  if (va < 15) {
+#if !REFRESH
+    for (int j = 15 - va; j > 0; --j) {
+      lcd.print(' ');
+    }
+#endif
+    ++i;
+  }
+  return i;
+}
+
+/*
+  Separate a substring that can be printed on one line, and return the 
+  original string position corresponding to the end of the substring.
+ */
+/*
+char* aux_sub_line(char* str, char substr[16]) {
+  int suf = 0;
+  char* curr = str;
+  memset(substr, 0, 16);
+  
+  while (*curr != '\0' && suf < 15) {
+    if (*curr != '\n' && *curr != '\r') {
+      substr[suf++] = *(curr++);
+    } else 
+    if (curr == str){ ++curr; } else 
+    {
+      break;
+    }
+  }
+  
+#if !REFRESH
+  while (suf < 15) {
+    substr[suf++] = ' ';
+  }
+#endif
+  return curr;
+}
+
+char* aux_sub_line_rev(char* str, char substr[16]) {
+  int suf = 0;
+  char* curr = str;
+  memset(substr, 0, 16);
+  
+  while (*curr != '\0' && suf < 15) {
+    if (*curr != '\n' && *curr != '\r') {
+      substr[suf++] = *(curr--);
+    } else 
+    if (curr == str){ --curr; } else 
+    {
+      break;
+    }
+  }
+  
+  
+}
+*/
+void lcd_blank_line() {
+  for (int i = 0; i < 15; ++i) {
+    lcd.print(' ');
+  }
+}