diff --git a/src/cursor.cc b/src/cursor.cc
index fcf9bdf..c3d04f8 100644
--- a/src/cursor.cc
+++ b/src/cursor.cc
@@ -2,53 +2,53 @@
 #include "constants.h"
 
 cursor::cursor() {
-    initscr();
+        initscr();
 
-    if (has_colors()) {
-        start_color();
-        init_pair(COLOR_RED, COLOR_RED, COLOR_BLACK);
-        init_pair(COLOR_GREEN, COLOR_GREEN, COLOR_BLACK);
-        init_pair(COLOR_YELLOW, COLOR_YELLOW, COLOR_BLACK);
-        init_pair(COLOR_BLUE, COLOR_BLUE, COLOR_BLACK);
-        init_pair(COLOR_MAGENTA, COLOR_MAGENTA, COLOR_BLACK);
-        init_pair(COLOR_CYAN, COLOR_CYAN, COLOR_BLACK);
-        init_pair(COLOR_WHITE, COLOR_WHITE, COLOR_BLACK);
-        init_pair(COLOR_BLACK_ON_WHITE, COLOR_BLACK, COLOR_WHITE);
-    }
+        if (has_colors()) {
+                start_color();
+                init_pair(COLOR_RED, COLOR_RED, COLOR_BLACK);
+                init_pair(COLOR_GREEN, COLOR_GREEN, COLOR_BLACK);
+                init_pair(COLOR_YELLOW, COLOR_YELLOW, COLOR_BLACK);
+                init_pair(COLOR_BLUE, COLOR_BLUE, COLOR_BLACK);
+                init_pair(COLOR_MAGENTA, COLOR_MAGENTA, COLOR_BLACK);
+                init_pair(COLOR_CYAN, COLOR_CYAN, COLOR_BLACK);
+                init_pair(COLOR_WHITE, COLOR_WHITE, COLOR_BLACK);
+                init_pair(COLOR_BLACK_ON_WHITE, COLOR_BLACK, COLOR_WHITE);
+        }
 }
 
 cursor::~cursor() {
-    endwin();
+        endwin();
 }
 
 int cursor::getcmd() const {
-    return getch();
+        return getch();
 }
 
 void cursor::show() const {
-    refresh();
+        refresh();
 }
 
 void cursor::clear() const {
-    ::clear();
+        ::clear();
 }
 
 void cursor::print_char(const position &pos, const char ch,
                         const int attrs) const {
-    attrset(attrs);
-    mvaddch(pos.y, pos.x, ch);
+        attrset(attrs);
+        mvaddch(pos.y, pos.x, ch);
 }
 
 void cursor::print_str(const position &pos, const std::string str,
                        const int attrs) const {
-    attrset(attrs);
-    mvaddstr(pos.y, pos.x, str.c_str());
+        attrset(attrs);
+        mvaddstr(pos.y, pos.x, str.c_str());
 }
 
 bool check_terminal_size() {
-    int max_x;
-    int max_y;
-    getmaxyx(stdscr, max_y, max_x);
+        int max_x;
+        int max_y;
+        getmaxyx(stdscr, max_y, max_x);
 
-    return max_x >= DISPLAY_WIDTH && max_y >= DISPLAY_HEIGHT;
+        return max_x >= DISPLAY_WIDTH && max_y >= DISPLAY_HEIGHT;
 }
diff --git a/src/cursor.h b/src/cursor.h
index 52fde78..c0e064a 100644
--- a/src/cursor.h
+++ b/src/cursor.h
@@ -37,20 +37,20 @@
 class cursor final {
 private:
 public:
-    cursor();
+        cursor();
 
-    ~cursor();
+        ~cursor();
 
-    int getcmd() const;
+        int getcmd() const;
 
-    void show() const;
+        void show() const;
 
-    void clear() const ;
+        void clear() const ;
 
-    void print_char(const position &pos, const char ch, const int attrs) const;
+        void print_char(const position &pos, const char ch, const int attrs) const;
 
-    void print_str(const position &head, const std::string str,
-                   const int attrs) const;
+        void print_str(const position &head, const std::string str,
+                       const int attrs) const;
 };
 
 // IMPORTANT: this will fail when terminal size changes
diff --git a/src/position.cc b/src/position.cc
index 75eb9e6..baf3aa5 100644
--- a/src/position.cc
+++ b/src/position.cc
@@ -5,43 +5,43 @@ position::position(): x{0}, y{0} {}
 position::position(int nx, int ny): x{nx}, y{ny} {}
 
 position position::operator+(const position &other) const {
-    position result{x + other.x, y + other.y};
-    return result;
+        position result{x + other.x, y + other.y};
+        return result;
 }
 
 position &position::operator=(const position &other) {
-    x = other.x;
-    y = other.y;
-    return *this;
+        x = other.x;
+        y = other.y;
+        return *this;
 }
 
 position &position::operator+=(const position &other) {
-    return *this = *this + other;
+        return *this = *this + other;
 }
 
 bool position::operator==(const position &other) const {
-    return x == other.x && y == other.y;
+        return x == other.x && y == other.y;
 }
 
 bool position::operator!=(const position &other) const {
-    return x != other.x || y != other.y;
+        return x != other.x || y != other.y;
 }
 
 bool position::operator<(const position &other) const {
-    return y < other.y || x < other.x;
+        return y < other.y || x < other.x;
 }
 
 #include <iostream>
 
 size_t find(const std::vector<position> &sorted_list,
             const position &target) {
-    // TODO: implement binary searching
+        // TODO: implement binary searching
 
-    for (size_t i = 0; i < sorted_list.size(); ++i)
-        if (sorted_list[i] == target)
-            return i;
+        for (size_t i = 0; i < sorted_list.size(); ++i)
+                if (sorted_list[i] == target)
+                        return i;
 
-    return sorted_list.size();
+        return sorted_list.size();
 }
 
 #include <algorithm>
diff --git a/src/rng.h b/src/rng.h
index 575311e..0abd2c2 100644
--- a/src/rng.h
+++ b/src/rng.h
@@ -11,20 +11,20 @@
 // IMPORTANT: pass all RNG objects as references
 class RNG final {
 private:
-    const unsigned int init_seed;
-    int curr_rand_num;
+        const unsigned int init_seed;
+        int curr_rand_num;
 public:
-    RNG(); // use time(0) as the seed
-    RNG(const unsigned int seed); // use a seed
+        RNG(); // use time(0) as the seed
+        RNG(const unsigned int seed); // use a seed
 
-    int rand_num(); // returns a random number between 0 and RAND_MAX
+        int rand_num(); // returns a random number between 0 and RAND_MAX
 
-    // IMPORTANT: all upper bounds are not included, all lower bounds are
-    int rand_between(const int lower_bound, const int upper_bound);
-    // returns a random number between 0 and upper_bound
-    int rand_under(const int upper_bound);
-    unsigned int get_init_seed() const;
-    int get_curr_rand_num() const;
+        // IMPORTANT: all upper bounds are not included, all lower bounds are
+        int rand_between(const int lower_bound, const int upper_bound);
+        // returns a random number between 0 and upper_bound
+        int rand_under(const int upper_bound);
+        unsigned int get_init_seed() const;
+        int get_curr_rand_num() const;
 
         bool trial(const fraction &psuccess);