diff --git a/tests/y_2022/test_2022_day0.py b/tests/y_1900/test_1900_day0.py
similarity index 93%
rename from tests/y_2022/test_2022_day0.py
rename to tests/y_1900/test_1900_day0.py
index e0b4a2e..854ca02 100644
--- a/tests/y_2022/test_2022_day0.py
+++ b/tests/y_1900/test_1900_day0.py
@@ -2,7 +2,7 @@
 
 from unittest.mock import mock_open, patch
 
-from y_2022.day0 import Day
+from y_1900.day0 import Day
 
 with patch("builtins.open", mock_open(read_data="0")):
     day = Day()
diff --git a/tests/y_2015/test_2015_day6.py b/tests/y_2015/test_2015_day6.py
new file mode 100644
index 0000000..ed76058
--- /dev/null
+++ b/tests/y_2015/test_2015_day6.py
@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from unittest.mock import mock_open, patch
+
+from y_2015.day6 import Day
+
+with patch("builtins.open", mock_open(read_data="command 0,0 through 999,999")):
+    day = Day()
+
+
+def test_calculate_1():
+    day._input_data = [["turn on 0,0 through 9,0", "turn off 8,0 through 9,0"]]
+    day._preprocess_input()
+    assert day._calculate_1() == 8
+
+    day._input_data = [["turn off 0,0 through 9,0"]]
+    day._preprocess_input()
+    assert day._calculate_1() == 0
+
+    day._input_data = [["toggle 0,0 through 9,0"]]
+    day._preprocess_input()
+    assert day._calculate_1() == 10
+
+
+def test_calculate_2():
+    day._input_data = [["turn on 0,0 through 0,0"]]
+    day._preprocess_input()
+    assert day._calculate_2() == 1
+
+    day._input_data = [["turn off 0,0 through 0,0"]]
+    day._preprocess_input()
+    assert day._calculate_2() == 0
+
+    day._input_data = [["toggle 0,0 through 0,0"]]
+    day._preprocess_input()
+    assert day._calculate_2() == 2
diff --git a/y_2022/day0.py b/y_1900/day0.py
similarity index 100%
rename from y_2022/day0.py
rename to y_1900/day0.py
diff --git a/y_2015/day3.py b/y_2015/day3.py
index 763613f..f6c869a 100644
--- a/y_2015/day3.py
+++ b/y_2015/day3.py
@@ -5,7 +5,7 @@
 from common.aoc import AoCDay
 
 
-@dataclass()
+@dataclass
 class Position:
     x: int
     y: int
diff --git a/y_2015/day6.py b/y_2015/day6.py
new file mode 100644
index 0000000..02573d0
--- /dev/null
+++ b/y_2015/day6.py
@@ -0,0 +1,84 @@
+import re
+from typing import Dict
+
+from pydantic.dataclasses import dataclass
+
+from common.aoc import AoCDay
+
+
+@dataclass
+class Instruction:
+    command: str
+    start_x: int
+    start_y: int
+    end_x: int
+    end_y: int
+
+    def process(self, grid, actions=None) -> None:
+        min_x = min(self.start_x, self.end_x)
+        min_y = min(self.start_y, self.end_y)
+        max_x = max(self.start_x, self.end_x)
+        max_y = max(self.start_y, self.end_y)
+
+        for i in range(min_x, max_x + 1):
+            for j in range(min_y, max_y + 1):
+                hash = Light.hash_fun(i, j)
+                if hash not in grid:
+                    grid[hash] = Light(i, j)
+                light = grid[hash]
+                light.brightness = actions[self.command](light.brightness)
+
+
+@dataclass
+class Light:
+    x: int
+    y: int
+    brightness: int = 0
+
+    @staticmethod
+    def hash_fun(x: int, y: int):
+        return f"x={x};y={y}"
+
+    @property
+    def hash(self) -> str:
+        return Light.hash_fun(self.x, self.y)
+
+
+class Day(AoCDay):
+    def __init__(self, test=0):
+        super().__init__(__name__, test)
+
+    def _preprocess_input(self):
+        self.__input_data = [
+            Instruction(
+                *list(re.search(r"(\D*) (\d*),(\d*) through (\d*),(\d*)", i).groups()),
+            )
+            for i in self._input_data[0]
+        ]
+
+    def _calculate_1(self) -> int:
+        grid: Dict[str, Light] = {}
+
+        actions = {
+            "turn on": lambda x: True,
+            "turn off": lambda x: False,
+            "toggle": lambda x: not x,
+        }
+        for i in self.__input_data:
+            i.process(grid, actions)
+
+        return sum(i.brightness for i in grid.values())
+
+    def _calculate_2(self) -> int:
+        grid: Dict[str, Light] = {}
+
+        actions = {
+            "turn on": lambda x: x + 1,
+            "turn off": lambda x: max(x - 1, 0),
+            "toggle": lambda x: x + 2,
+        }
+
+        for i in self.__input_data:
+            i.process(grid, actions)
+
+        return sum(i.brightness for i in grid.values())