diff --git a/src/directions.c b/src/directions.c
new file mode 100644
index 0000000..572c520
--- /dev/null
+++ b/src/directions.c
@@ -0,0 +1,80 @@
+/* CATWALK - Test your logic
+   Copyright (C) 2021 Valentin Moguerou
+   
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULIAR PURPOSE. See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>  */
+
+#include <stdlib.h>
+#include "../inc/directions.h"
+#include "../inc/route.h"
+
+#define RANDINT(MAX) (rand() % MAX)
+
+directions *init_directions(route *rt)
+{
+    directions *dirs = malloc(sizeof(*dirs));
+    if (dirs==NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    dirs->rt = rt;
+    dirs->count = 0;
+
+    return dirs;
+}
+
+int evaluate_directions(directions *dirs)
+{
+    int width = dirs->rt->width;
+    element *last = dirs->rt->last;
+
+    int count = 0;
+    if (last->x != 0 && is_free(dirs->rt, last->x-1, last->y))
+    {
+        dirs->cells[count][0] = last->x-1;
+        dirs->cells[count][1] = last->y;
+        count++;
+    }
+    if (last->x != (width-1) && is_free(dirs->rt, last->x+1, last->y))
+    {
+        dirs->cells[count][0] = last->x+1;
+        dirs->cells[count][1] = last->y;
+        count++;
+    }
+    if (last->y != 0 && is_free(dirs->rt, last->x, last->y-1))
+    {
+        dirs->cells[count][0] = last->x;
+        dirs->cells[count][1] = last->y-1;
+        count++;
+    }
+    if (last->y != (width-1) && is_free(dirs->rt, last->x, last->y+1))
+    {
+        dirs->cells[count][0] = last->x;
+        dirs->cells[count][1] = last->y+1;
+        count++;
+    }
+    dirs->count = count;
+    return count;
+}
+
+void push_choose(route *rt, directions *dirs)
+{
+    int nb = RANDINT(dirs->count);
+    push_back(rt, dirs->cells[nb][0], dirs->cells[nb][1]);
+}
+
+void delete_directions(directions *dirs)
+{
+    free(dirs);
+}
\ No newline at end of file
diff --git a/src/grid.c b/src/grid.c
new file mode 100644
index 0000000..adc4f27
--- /dev/null
+++ b/src/grid.c
@@ -0,0 +1,108 @@
+/* CATWALK - Test your logic
+   Copyright (C) 2021 Valentin Moguerou
+   
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULIAR PURPOSE. See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>  */
+
+#include <stdlib.h>
+#include "../inc/grid.h"
+#include "../inc/indicators.h"
+#include "../inc/route.h"
+
+#define RANDINT(MAX) (rand() % MAX)
+
+grid *init_grid(int width)
+{
+    grid *gd = malloc(sizeof(grid));
+    if (gd == NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    gd->width = width;
+    gd->hints = init_indicators(width);
+    gd->player_route = NULL;
+
+    return gd;
+}
+
+void random_grid(grid *gd, int seed)
+{
+    srand(seed);
+    random_start(gd);
+    refresh_grid(gd);
+}
+
+void random_start(grid *gd)
+{
+    gd->start[0] = RANDINT(gd->width);
+    gd->start[1] = RANDINT(gd->width);
+}
+
+void refresh_grid(grid *gd)
+{
+    route *rt = init_route(gd->width, gd->start[0], gd->start[1]);
+
+    generate(rt);
+    setup_indicators(gd->hints, rt);
+    
+    element *last = rt->last;
+    gd->end[0] = last->x;
+    gd->end[1] = last->y;
+    
+    delete_route(rt);
+}
+
+void init_player_route(grid *gd)
+{
+    route *player_rt = malloc(sizeof(*player_rt));
+    if (player_rt == NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    player_rt = init_route(gd->width, gd->start[0], gd->start[1]);
+
+    gd->player_route = player_rt;
+}
+
+void reset_player_route(grid *gd)
+{
+    delete_route(gd->player_route);
+    init_player_route(gd);
+}
+
+void delete_grid(grid *gd)
+{
+    delete_indicators(gd->hints);
+    if (gd->player_route)
+    {
+        delete_route(gd->player_route);
+    }
+    free(gd);
+}
+
+int verify(grid *gd)
+{
+    indicators *verif_in = init_indicators(gd->width);
+    setup_indicators(verif_in, gd->player_route);
+
+    for (int i=0; i<gd->width; i++)
+    {
+        if ((verif_in->x[i] != gd->hints->x[i]) || (verif_in->y[i] != gd->hints->y[i]))
+        {
+            return 0;
+        }
+    }
+    return 1;
+}
\ No newline at end of file
diff --git a/src/indicators.c b/src/indicators.c
new file mode 100644
index 0000000..4c1ba24
--- /dev/null
+++ b/src/indicators.c
@@ -0,0 +1,58 @@
+/* CATWALK - Test your logic
+   Copyright (C) 2021 Valentin Moguerou
+   
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULIAR PURPOSE. See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>  */
+
+#include <stdlib.h>
+#include "../inc/indicators.h"
+#include "../inc/route.h"
+
+indicators *init_indicators(int width)
+{
+    indicators *in = malloc(sizeof(*in));
+    if (in == NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    in->x = calloc(width, sizeof(int));
+    in->y = calloc(width, sizeof(int));
+    if (in->x==NULL || in->y==NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    return in;
+}
+
+void setup_indicators(indicators *in, route *rt)
+{
+    for (int i=0; i<rt->width; i++)
+    {
+        in->x[i] = 0;
+        in->y[i] = 0;
+    }
+    for (element *el=rt->first; el; el=el->next)
+    {
+        in->x[el->x]++;
+        in->y[el->y]++;
+    }
+}
+
+void delete_indicators(indicators *hints)
+{
+    free(hints->x);
+    free(hints->y);
+    free(hints);
+}
diff --git a/src/route.c b/src/route.c
new file mode 100644
index 0000000..4b0249e
--- /dev/null
+++ b/src/route.c
@@ -0,0 +1,210 @@
+/* CATWALK - Test your logic
+   Copyright (C) 2021 Valentin Moguerou
+   
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULIAR PURPOSE. See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>  */
+
+#include <stdlib.h>
+#include "../inc/directions.h"
+#include "../inc/route.h"
+
+#define RANDINT(MIN, MAX) ((rand()%(MAX-MIN)) + MIN)
+
+int is_left(element *first, element *second)
+{
+    return first->x-1 == second->x;
+}
+
+int is_right(element *first, element *second)
+{
+    return first->x+1 == second->x;
+}
+
+int is_up(element *first, element *second)
+{
+    return first->y-1 == second->y;
+}
+
+int is_down(element *first, element *second)
+{
+    return first->y+1 == second->y;
+}
+
+int move_left(route *rt)
+{
+    element *last = rt->last;
+    if (last->x == 0)
+    {
+        return 1;
+    }
+    else if (!is_free(rt, last->x-1, last->y))
+    {
+        return 2;
+    }
+    else
+    {
+        push_back(rt, last->x-1, last->y);
+        return 0;
+    }
+}
+
+int move_right(route *rt)
+{
+    element *last = rt->last;
+    if (last->x == rt->width-1)
+    {
+        return 1;
+    }
+    else if (!is_free(rt, last->x+1, last->y))
+    {
+        return 2;
+    }
+    else
+    {
+        push_back(rt, last->x+1, last->y);
+        return 0;
+    }
+}
+
+int move_up(route *rt)
+{
+    element *last = rt->last;
+    if (last->y == 0)
+    {
+        return 1;
+    }
+    else if (!is_free(rt, last->x, last->y-1))
+    {
+        return 2;
+    }
+    else
+    {
+        push_back(rt, last->x, last->y-1);
+        return 0;
+    }
+}
+
+int move_down(route *rt)
+{
+    element *last = rt->last;
+    if (last->y == (rt->width-1))
+    {
+        return 1;
+    }
+    else if (!is_free(rt, last->x, last->y+1))
+    {
+        return 2;
+    }
+    else
+    {
+        push_back(rt, last->x, last->y+1);
+        return 0;
+    }
+}
+
+route *init_route(int width, int startx, int starty)
+{
+    route *rt = malloc(sizeof(*rt));
+    element *el = malloc(sizeof(*el));
+
+    if (rt == NULL || el == NULL)
+    {
+        exit(EXIT_FAILURE); // memory allocation failed
+    }
+
+    el->previous = NULL;
+    el->next = NULL;
+
+    el->x = startx;
+    el->y = starty;
+
+    rt->width = width;
+    rt->first = el;
+    rt->last = el;
+
+    return rt;
+}
+
+void delete_element(element *el)
+{
+    if (el->next)
+    {
+        delete_element(el->next);
+    }
+    free(el);
+}
+
+void delete_route(route *rt)
+{
+    delete_element(rt->first);
+    free(rt);
+}
+
+void push_back(route *rt, int x, int y)
+{
+    element *new_el = malloc(sizeof(*new_el));
+    if (new_el == NULL)
+    {
+        exit(EXIT_FAILURE);
+    }
+
+    new_el->x = x;
+    new_el->y = y;
+    new_el->previous = rt->last;
+    new_el->next = NULL;
+
+    rt->last->next = new_el;
+    rt->last = new_el;
+}
+
+void pop_back(route *rt)
+{
+    element *last = rt->last;
+    rt->last = rt->last->previous;
+    rt->last->next = NULL;
+    free(last);
+}
+
+element *find_coordinates(route *rt, int x, int y)
+{
+    for (element *el=rt->first; el; el=el->next)
+    {
+        if (el->x == x && el->y == y)
+        {
+            return el;
+        }
+    }
+    return NULL;
+}
+
+int is_free(route *rt, int x, int y)
+{
+    for (element *el=rt->first; el; el=el->next)
+    {
+        if (x==el->x && y==el->y)
+        {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+void generate(route *rt)
+{
+    directions *dirs = init_directions(rt);
+
+    for (int i=0; i < RANDINT(1, rt->width*rt->width) && evaluate_directions(dirs); i++)
+    {
+        push_choose(rt, dirs);
+    }
+}
\ No newline at end of file