diff --git a/solutions/gmacario/day04-jupyter/day04.ipynb b/solutions/gmacario/day04-jupyter/day04.ipynb
index f6b20b1..239a679 100644
--- a/solutions/gmacario/day04-jupyter/day04.ipynb
+++ b/solutions/gmacario/day04-jupyter/day04.ipynb
@@ -41,7 +41,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 29,
+   "execution_count": 3,
    "id": "992b746b-12f1-4576-ae26-f3c5d379c844",
    "metadata": {},
    "outputs": [],
@@ -90,7 +90,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 30,
+   "execution_count": 4,
    "id": "2672708d-3eec-4410-80bd-2e5cb40f6ab3",
    "metadata": {},
    "outputs": [],
@@ -121,7 +121,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 31,
+   "execution_count": 5,
    "id": "8d23c8b5-785f-4bfb-8702-f16a064d607b",
    "metadata": {},
    "outputs": [],
@@ -149,12 +149,116 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 32,
+   "execution_count": 6,
+   "id": "5bd62597-fcb7-47ea-87c7-b926c93630b3",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def char_at(board, position):\n",
+    "    \"\"\"\n",
+    "    Find a character on board\n",
+    "    Return a string with the character\n",
+    "    \"\"\"\n",
+    "\n",
+    "    height = len(board)\n",
+    "    width = len(board[0])\n",
+    "    \n",
+    "    assert position[0] >= 0 and position[0] < width, f\"{ic(word, board, position)}\"\n",
+    "    assert position[1] >= 0 and position[1] < height, f\"{ic(word, board, position)}\"\n",
+    "\n",
+    "    board_char = board[height - position[1] - 1][position[0]]\n",
+    "    \n",
+    "    return board_char"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "38ba741d-7b92-474b-bf73-f479cffdb44d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def find_cross_at_pos(board, position):\n",
+    "\n",
+    "    width = len(board[0])\n",
+    "    height = len(board)\n",
+    "\n",
+    "    total = 0\n",
+    "\n",
+    "    x = position[0]\n",
+    "    y = position[1]\n",
+    "\n",
+    "    # ic(\"find_cross_at_pos\", x, y)\n",
+    "\n",
+    "    if x < 1 or x+1 > width - 1:\n",
+    "        return 0\n",
+    "    if y < 1 or y+1 > height - 1:\n",
+    "        return 0\n",
+    "    \n",
+    "    if char_at(board, (x, y)) != \"A\":\n",
+    "        return 0\n",
+    "        \n",
+    "    # ic(f\"A found at ({x},{y})\")\n",
+    "    \n",
+    "    if char_at(board, (x-1, y+1)) == \"M\" and char_at(board, (x+1, y-1)) == \"S\":\n",
+    "        if char_at(board, (x-1, y-1)) == \"M\" and char_at(board, (x+1, y+1)) == \"S\":\n",
+    "            return 1\n",
+    "        elif char_at(board, (x-1, y-1)) == \"S\" and char_at(board, (x+1, y+1)) == \"M\":\n",
+    "            return 1\n",
+    "        else:\n",
+    "            return 0\n",
+    "\n",
+    "    if char_at(board, (x-1, y+1)) == \"S\" and char_at(board, (x+1, y-1)) == \"M\":\n",
+    "        if char_at(board, (x-1, y-1)) == \"M\" and char_at(board, (x+1, y+1)) == \"S\":\n",
+    "            return 1\n",
+    "        elif char_at(board, (x-1, y-1)) == \"S\" and char_at(board, (x+1, y+1)) == \"M\":\n",
+    "            return 1\n",
+    "        else:\n",
+    "            return 0\n",
+    "    \n",
+    "    return 0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "8e7df71f-c2c7-411b-8f16-4f7b4d30522a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def find_cross_in_board(board):\n",
+    "\n",
+    "    width = len(board[0])\n",
+    "    height = len(board)\n",
+    "    \n",
+    "    # ic(width, height, board)\n",
+    "    \n",
+    "    total = 0\n",
+    "\n",
+    "    for x in range(1, width-1):\n",
+    "        for y in range(1, height-1):\n",
+    "            total += find_cross_at_pos(board, (x, y))                \n",
+    "            ...\n",
+    "    \n",
+    "    return total"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "77466af9-01cd-45e3-b37c-bcaf0e716aab",
+   "metadata": {},
+   "source": [
+    "## Test Patterns"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
    "id": "a8c2b044-3430-42b6-bb94-95d56950bd2c",
    "metadata": {},
    "outputs": [],
    "source": [
-    "test1 = \"\"\"..X...\n",
+    "part1_test1 = \"\"\"..X...\n",
     ".SAMX.\n",
     ".A..A.\n",
     "XMAS.S\n",
@@ -164,12 +268,12 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": 10,
    "id": "96c152a4-182b-463e-8dcc-42b20ab9916a",
    "metadata": {},
    "outputs": [],
    "source": [
-    "test2 = \"\"\"MMMSXXMASM\n",
+    "part1_test2 = \"\"\"MMMSXXMASM\n",
     "MSAMXMSMSA\n",
     "AMXSXMAAMM\n",
     "MSAMASMSMX\n",
@@ -184,7 +288,48 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 39,
+   "execution_count": 11,
+   "id": "0cb79ad0-9479-46cf-aaa3-2d68152e3f77",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "part2_test1 = \"\"\"M.S\n",
+    ".A.\n",
+    "M.S\n",
+    "\"\"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "id": "dd72bd6a-eb4e-4799-8c44-5e0721fd368e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "part2_test2 = \"\"\".M.S......\n",
+    "..A..MSMS.\n",
+    ".M.S.MAA..\n",
+    "..A.ASMSM.\n",
+    ".M.S.M....\n",
+    "..........\n",
+    "S.S.S.S.S.\n",
+    ".A.A.A.A..\n",
+    "M.M.M.M.M.\n",
+    "..........\n",
+    "\"\"\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3c8038fc-40c1-4442-bd9d-59270c178ed1",
+   "metadata": {},
+   "source": [
+    "## Parse input"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
    "id": "9cf5cd67-c278-4037-8002-bc6b9308193d",
    "metadata": {},
    "outputs": [],
@@ -196,8 +341,12 @@
     "with open(FILENAME, 'r') as file:\n",
     "    input_text = file.read()\n",
     "\n",
-    "# input_text = test1 # DEBUG\n",
-    "# input_text = test2 # DEBUG\n",
+    "# input_text = part1_test1 # DEBUG\n",
+    "# input_text = part1_test2 # DEBUG\n",
+    "\n",
+    "# input_text = part2_test1 # DEBUG\n",
+    "# input_text = part2_test2 # DEBUG\n",
+    "\n",
     "# ic(input_text)\n",
     "\n",
     "lineno = 0\n",
@@ -209,7 +358,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 40,
+   "execution_count": 14,
    "id": "fb02256a-b564-4242-9635-6f6e276a9577",
    "metadata": {
     "scrolled": true
@@ -221,14 +370,22 @@
     "# ic(checkerboard)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "a7d266d2-d9c7-4a79-9df3-3574da1d0ba3",
+   "metadata": {},
+   "source": [
+    "## Part 1: Find XMAS"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 41,
+   "execution_count": 15,
    "id": "7fe4596c-be12-4002-824a-3836cb351d5c",
    "metadata": {},
    "outputs": [],
    "source": [
-    "# test1\n",
+    "# part1_test1\n",
     "#\n",
     "# find_word_across(\"XMAS\", checkerboard, (0,1), \"E\")\n",
     "#\n",
@@ -237,25 +394,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 42,
+   "execution_count": 16,
    "id": "db67d781-8902-44a2-97c3-d9402a8686eb",
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "text/plain": [
-       "0"
-      ]
-     },
-     "execution_count": 42,
-     "metadata": {},
-     "output_type": "execute_result"
-    }
-   ],
+   "outputs": [],
    "source": [
-    "# test2\n",
+    "# part1_test2\n",
     "#\n",
-    "find_word_across(\"XMAS\", checkerboard, (3,0), \"NW\")\n",
+    "# find_word_across(\"XMAS\", checkerboard, (3,0), \"NW\")\n",
     "# find_word_across(\"XMAS\", checkerboard, (9,6), \"S\")\n",
     "# find_word_across(\"XMAS\", checkerboard, (5,9), \"E\")\n",
     "# find_word_across(\"XMAS\", checkerboard, (9,6), \"S\")\n",
@@ -266,7 +412,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 43,
+   "execution_count": 17,
    "id": "f3764b52-eec3-44b4-baee-90fff6e6a837",
    "metadata": {},
    "outputs": [
@@ -283,7 +429,7 @@
        "2642"
       ]
      },
-     "execution_count": 43,
+     "execution_count": 17,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -293,17 +439,38 @@
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "b646299e-fb4e-4b39-bd1e-cf0a15421ebe",
+   "cell_type": "markdown",
+   "id": "e87a9ec5-652a-4168-8fbf-9eb0fca73e3d",
    "metadata": {
     "collapsed": true,
     "jupyter": {
      "outputs_hidden": true
     }
    },
-   "outputs": [],
-   "source": []
+   "source": [
+    "## Part 2: Find X-MAS"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "id": "6848e4af-67c7-4289-8f28-0a227aaa670d",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "1974"
+      ]
+     },
+     "execution_count": 18,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "find_cross_in_board(checkerboard)"
+   ]
   }
  ],
  "metadata": {