diff --git a/conway/game.py b/conway/game.py
index d147be5..6d2b56e 100644
--- a/conway/game.py
+++ b/conway/game.py
@@ -42,6 +42,8 @@ class Game:
                 raise InitError("Please make sure that the seed matches \
                                  the provided width and height values.")
 
+            self._scan_seed(seed)
+
             self.seed = seed
             self.live_cells = self._count_live_cells(self.seed)
 
@@ -68,6 +70,17 @@ class Game:
         dim_one = [0 for row in range(rows)]
         return [dim_one[:] for col in range(cols)]
 
+    def _scan_seed(self, seed: list):
+        """
+        Scans each cell in a seed to make sure that only valid data (0, 1)
+        is present. Throws an InitError exception, if not.
+        """
+        for row in seed:
+            for item in row:
+                if item != 0 and item != 1:
+                    raise InitError("Game seed can only contain 0s \
+                                 and 1s.")
+
     def _num_neighbors(self, row: int, column: int) -> int:
         """
         Determine the number of neighbors to a given cell that

make sure that the provided beacon only contains ones and zeroes
diff --git a/tests/tests.py b/tests/tests.py
index 548e82f..60bbf02 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -255,3 +255,28 @@ class TestConway():
         test_game.stop()
 
         assert test_game.state, GameState.FINISHED
+
+    def test_ensure_that_seed_includes_valid_data(self):
+        seed = [['a', 0, 0, 0],
+                [0, 2, 1, 0],
+                [0, 1, 1, 0],
+                [0, 0, 0, -1]]
+
+        with pytest.raises(InitError):
+            Game(4, 4, seed)
+
+        seed = [[0, 0, 0, 0],
+                [0, 2, 1, 0],
+                [0, 1, 1, 0],
+                [0, 0, 0, -1]]
+
+        with pytest.raises(InitError):
+            Game(4, 4, seed)
+
+        seed = [[0, 0, 0, 0],
+                [0, 0, 1, 0],
+                [0, 1, 1, 0],
+                [0, 0, 0, -1]]
+
+        with pytest.raises(InitError):
+            Game(4, 4, seed)

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest>=4.4.0 pytest-cov pytest-ordering pytest-subtests pytest-timeout pytest
3.9
requirements-dev.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs==25.3.0
coverage==7.8.0
exceptiongroup==1.2.2
iniconfig==2.1.0
packaging==24.2
pluggy==1.5.0
-e git+https://github.com/bsatrom/py-conway.git@4271eb5fe31e47ff91b78472c9c88a55fe4291a6#egg=py_conway
pytest==8.3.5
pytest-cov==6.0.0
pytest-ordering==0.6
pytest-subtests==0.14.1
pytest-timeout==2.3.1
tomli==2.2.1

name: py-conway
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - attrs==25.3.0
      - coverage==7.8.0
      - exceptiongroup==1.2.2
      - iniconfig==2.1.0
      - packaging==24.2
      - pluggy==1.5.0
      - pytest==8.3.5
      - pytest-cov==6.0.0
      - pytest-ordering==0.6
      - pytest-subtests==0.14.1
      - pytest-timeout==2.3.1
      - tomli==2.2.1
prefix: /opt/conda/envs/py-conway

tests/tests.py::TestConway::test_ensure_that_seed_includes_valid_data
tests/tests.py::TestConway::test_game_init tests/tests.py::TestConway::test_test_game_init_seed tests/tests.py::TestConway::test_test_game_init_defaults tests/tests.py::TestConway::test_test_game_init_board_default_seed tests/tests.py::TestConway::test_test_game_3_x_3_check_cell_with_one_neighbor tests/tests.py::TestConway::test_test_game_3_x_3_check_cell_with_two_neighbors tests/tests.py::TestConway::test_test_game_3_x_3_check_cell_with_three_neighbors tests/tests.py::TestConway::test_single_column_array tests/tests.py::TestConway::test_3_x_3_single_cell_single_run tests/tests.py::TestConway::test_3_x_3_three_neighbors_single_run tests/tests.py::TestConway::test_3_x_3_four_neighbors_single_run tests/tests.py::TestConway::test_4_x_3_three_neighbors_single_run tests/tests.py::TestConway::test_3_x_3_empty_seed_no_live_cells tests/tests.py::TestConway::test_3_x_3_seed_five_live_cells tests/tests.py::TestConway::test_increment_live_cells_after_update tests/tests.py::TestConway::test_update_generations_count_after_each_generation tests/tests.py::TestConway::test_3_x_3_four_neighbors_two_runs tests/tests.py::TestConway::test_default_game_state_ready tests/tests.py::TestConway::test_start_game_changes_state_to_running tests/tests.py::TestConway::test_empty_board_run_game_until_no_living_cells_left tests/tests.py::TestConway::test_ensure_that_width_height_and_seed_match tests/tests.py::TestConway::test_ensure_that_live_cells_count_is_accurate_before_run tests/tests.py::TestConway::test_no_seed_ensure_live_cells_count_is_accurate_before_run tests/tests.py::TestConway::test_still_life_game_will_continue_to_run tests/tests.py::TestConway::test_still_life_game_can_be_stopped
conway/game.py
conway/game.py