diff --git a/README.md b/README.md
index d1eccd4..f3331f5 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ To arrive at [⟨ortho|normal⟩](https://hilb.ert.space) as December comes.
 | 06  | ~ 3         |
 | 07  | ~ 1         |
 | 08  | ~ 6.5       |
-| 09  |             |
+| 09  | ~ 7         |
 | 10  |             |
 | 11  |             |
 | 12  |             |
diff --git a/app/Main.hs b/app/Main.hs
index e48b8d4..362fe14 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -30,4 +30,4 @@ import qualified Day24
 import qualified Day25
 
 main :: IO ()
-main = Day09.main
+main = Day10.main
diff --git a/input/10.txt b/input/10.txt
new file mode 100644
index 0000000..c8f8d4c
--- /dev/null
+++ b/input/10.txt
@@ -0,0 +1,328 @@
+position=< 42772, -21149> velocity=<-4,  2>
+position=< 42804, -31790> velocity=<-4,  3>
+position=<-10445, -10502> velocity=< 1,  1>
+position=<-31749,  21438> velocity=< 3, -2>
+position=<-31722,  32074> velocity=< 3, -3>
+position=< 53436, -21147> velocity=<-5,  2>
+position=<-42336, -42437> velocity=< 4,  4>
+position=<-42380,  21435> velocity=< 4, -2>
+position=< 21508, -10506> velocity=<-2,  1>
+position=<-31727,  42725> velocity=< 3, -4>
+position=<-42383,  32083> velocity=< 4, -3>
+position=< 42764,  21438> velocity=<-4, -2>
+position=<-53037, -53086> velocity=< 5,  5>
+position=< 53436, -10506> velocity=<-5,  1>
+position=<-10445,  32083> velocity=< 1, -3>
+position=<-53001, -53081> velocity=< 5,  5>
+position=<-31724, -21151> velocity=< 3,  2>
+position=<-21106,  42720> velocity=< 2, -4>
+position=< 10847, -53083> velocity=<-1,  5>
+position=< 21483, -21147> velocity=<-2,  2>
+position=< 53433, -21146> velocity=<-5,  2>
+position=< 32121,  42719> velocity=<-3, -4>
+position=< 10834,  53364> velocity=<-1, -5>
+position=<-31708, -42434> velocity=< 3,  4>
+position=<-21057, -10497> velocity=< 2,  1>
+position=<-42372, -53082> velocity=< 4,  5>
+position=< 32143, -10502> velocity=<-3,  1>
+position=<-31751, -53078> velocity=< 3,  5>
+position=<-21069,  42720> velocity=< 2, -4>
+position=<-21049, -42432> velocity=< 2,  4>
+position=<-42376,  42727> velocity=< 4, -4>
+position=< 42790, -21151> velocity=<-4,  2>
+position=< 10849,  32082> velocity=<-1, -3>
+position=<-31724, -21142> velocity=< 3,  2>
+position=< 32159, -10498> velocity=<-3,  1>
+position=< 32180, -21151> velocity=<-3,  2>
+position=< 21491,  53368> velocity=<-2, -5>
+position=< 32162, -21149> velocity=<-3,  2>
+position=< 21482, -10505> velocity=<-2,  1>
+position=<-52981, -53079> velocity=< 5,  5>
+position=< 42796,  32079> velocity=<-4, -3>
+position=<-21066,  42720> velocity=< 2, -4>
+position=< 10862,  32083> velocity=<-1, -3>
+position=< 21474, -53083> velocity=<-2,  5>
+position=<-10434, -10497> velocity=< 1,  1>
+position=<-21054,  53364> velocity=< 2, -5>
+position=< 21534,  42723> velocity=<-2, -4>
+position=< 10861, -21147> velocity=<-1,  2>
+position=< 10857, -10502> velocity=<-1,  1>
+position=< 53461,  32079> velocity=<-5, -3>
+position=< 32132, -10505> velocity=<-3,  1>
+position=<-42362, -21142> velocity=< 4,  2>
+position=<-42396,  32074> velocity=< 4, -3>
+position=< 53469, -21151> velocity=<-5,  2>
+position=<-21098,  42723> velocity=< 2, -4>
+position=<-42378,  32080> velocity=< 4, -3>
+position=<-21074,  42726> velocity=< 2, -4>
+position=< 10881, -10500> velocity=<-1,  1>
+position=< 21514,  53367> velocity=<-2, -5>
+position=< 42764, -53080> velocity=<-4,  5>
+position=< 32151,  53368> velocity=<-3, -5>
+position=<-21090,  21437> velocity=< 2, -2>
+position=< 10877, -53078> velocity=<-1,  5>
+position=<-10445, -31796> velocity=< 1,  3>
+position=< 42796,  42722> velocity=<-4, -4>
+position=<-31740, -21147> velocity=< 3,  2>
+position=<-42344, -53083> velocity=< 4,  5>
+position=<-21087, -31794> velocity=< 2,  3>
+position=<-31691,  32082> velocity=< 3, -3>
+position=< 21490, -31790> velocity=<-2,  3>
+position=< 42792, -10506> velocity=<-4,  1>
+position=< 53462,  32074> velocity=<-5, -3>
+position=<-53025,  53366> velocity=< 5, -5>
+position=<-31722,  21438> velocity=< 3, -2>
+position=< 53469,  10786> velocity=<-5, -1>
+position=< 10841,  32081> velocity=<-1, -3>
+position=< 53449,  21431> velocity=<-5, -2>
+position=<-21074, -10501> velocity=< 2,  1>
+position=< 21487, -53084> velocity=<-2,  5>
+position=<-53015, -53082> velocity=< 5,  5>
+position=< 42777, -31787> velocity=<-4,  3>
+position=< 42764, -10502> velocity=<-4,  1>
+position=< 53422,  10787> velocity=<-5, -1>
+position=< 42772, -10503> velocity=<-4,  1>
+position=< 53465,  32081> velocity=<-5, -3>
+position=<-10421,  10793> velocity=< 1, -1>
+position=< 42815, -42432> velocity=<-4,  4>
+position=<-21106, -53079> velocity=< 2,  5>
+position=<-53033,  53369> velocity=< 5, -5>
+position=< 42766,  53368> velocity=<-4, -5>
+position=< 42767, -21151> velocity=<-4,  2>
+position=< 21526, -31789> velocity=<-2,  3>
+position=<-21082, -21148> velocity=< 2,  2>
+position=< 53410, -21147> velocity=<-5,  2>
+position=<-31691, -10500> velocity=< 3,  1>
+position=< 42805,  32078> velocity=<-4, -3>
+position=<-42378, -31790> velocity=< 4,  3>
+position=<-21050, -21143> velocity=< 2,  2>
+position=<-21106, -42436> velocity=< 2,  4>
+position=<-53001,  53365> velocity=< 5, -5>
+position=< 53469, -21145> velocity=<-5,  2>
+position=< 10833, -31796> velocity=<-1,  3>
+position=<-53009, -10498> velocity=< 5,  1>
+position=< 32159, -31789> velocity=<-3,  3>
+position=<-53007, -53077> velocity=< 5,  5>
+position=< 21474, -21149> velocity=<-2,  2>
+position=< 53427, -53083> velocity=<-5,  5>
+position=< 10861,  42720> velocity=<-1, -4>
+position=<-53017,  10786> velocity=< 5, -1>
+position=<-42335, -42441> velocity=< 4,  4>
+position=<-31751, -42432> velocity=< 3,  4>
+position=< 32171,  21429> velocity=<-3, -2>
+position=<-53016, -53086> velocity=< 5,  5>
+position=< 21522,  21436> velocity=<-2, -2>
+position=<-53009, -53079> velocity=< 5,  5>
+position=< 53433,  42721> velocity=<-5, -4>
+position=< 53420, -42441> velocity=<-5,  4>
+position=< 42777, -10504> velocity=<-4,  1>
+position=<-10416,  32074> velocity=< 1, -3>
+position=<-42396,  10788> velocity=< 4, -1>
+position=< 21490,  10791> velocity=<-2, -1>
+position=< 32128, -21147> velocity=<-3,  2>
+position=< 53461, -21143> velocity=<-5,  2>
+position=<-21063, -21149> velocity=< 2,  2>
+position=<-31743, -31792> velocity=< 3,  3>
+position=< 21514,  21432> velocity=<-2, -2>
+position=< 10861,  10791> velocity=<-1, -1>
+position=< 10881, -31792> velocity=<-1,  3>
+position=< 10889, -31795> velocity=<-1,  3>
+position=< 32143, -21145> velocity=<-3,  2>
+position=<-21093, -42439> velocity=< 2,  4>
+position=<-10450,  21433> velocity=< 1, -2>
+position=<-31719,  21430> velocity=< 3, -2>
+position=< 10865,  53373> velocity=<-1, -5>
+position=<-10405, -21144> velocity=< 1,  2>
+position=< 21534, -42433> velocity=<-2,  4>
+position=<-31727, -53083> velocity=< 3,  5>
+position=<-53021,  21437> velocity=< 5, -2>
+position=< 53449, -42434> velocity=<-5,  4>
+position=<-21046,  10789> velocity=< 2, -1>
+position=< 21518,  32082> velocity=<-2, -3>
+position=<-31727, -10506> velocity=< 3,  1>
+position=<-53033,  10793> velocity=< 5, -1>
+position=< 10842, -10498> velocity=<-1,  1>
+position=< 53425,  32075> velocity=<-5, -3>
+position=<-53004,  32082> velocity=< 5, -3>
+position=<-53016, -53082> velocity=< 5,  5>
+position=<-21098,  21435> velocity=< 2, -2>
+position=<-10417,  42720> velocity=< 1, -4>
+position=<-42363,  21429> velocity=< 4, -2>
+position=< 32151,  10790> velocity=<-3, -1>
+position=<-53025,  21431> velocity=< 5, -2>
+position=<-10437, -42435> velocity=< 1,  4>
+position=<-31735, -10502> velocity=< 3,  1>
+position=<-21098, -21149> velocity=< 2,  2>
+position=< 10830,  10784> velocity=<-1, -1>
+position=< 10838, -21151> velocity=<-1,  2>
+position=<-21085, -21142> velocity=< 2,  2>
+position=< 32119, -53079> velocity=<-3,  5>
+position=<-31700,  21438> velocity=< 3, -2>
+position=<-31714, -31795> velocity=< 3,  3>
+position=< 32135, -10504> velocity=<-3,  1>
+position=< 10889, -21149> velocity=<-1,  2>
+position=<-31742, -53086> velocity=< 3,  5>
+position=<-31726, -42432> velocity=< 3,  4>
+position=<-31727, -53079> velocity=< 3,  5>
+position=<-42369, -31792> velocity=< 4,  3>
+position=< 10830, -42437> velocity=<-1,  4>
+position=< 32179,  42725> velocity=<-3, -4>
+position=< 21483, -31796> velocity=<-2,  3>
+position=< 53435,  32074> velocity=<-5, -3>
+position=< 32132, -31788> velocity=<-3,  3>
+position=< 53449,  10787> velocity=<-5, -1>
+position=<-21066, -42439> velocity=< 2,  4>
+position=<-21065,  10789> velocity=< 2, -1>
+position=<-31693, -31787> velocity=< 3,  3>
+position=<-42380,  42727> velocity=< 4, -4>
+position=< 42788,  10785> velocity=<-4, -1>
+position=<-21054, -21150> velocity=< 2,  2>
+position=< 42772, -42434> velocity=<-4,  4>
+position=<-31722,  42719> velocity=< 3, -4>
+position=< 10837, -31794> velocity=<-1,  3>
+position=< 21498, -42436> velocity=<-2,  4>
+position=< 42797,  10793> velocity=<-4, -1>
+position=<-42372,  42724> velocity=< 4, -4>
+position=< 32171,  10787> velocity=<-3, -1>
+position=<-21085, -42441> velocity=< 2,  4>
+position=<-21046,  10791> velocity=< 2, -1>
+position=<-31709,  53370> velocity=< 3, -5>
+position=< 21503,  21438> velocity=<-2, -2>
+position=<-31695, -10498> velocity=< 3,  1>
+position=<-10411, -53077> velocity=< 1,  5>
+position=< 32169,  21438> velocity=<-3, -2>
+position=< 53454, -42441> velocity=<-5,  4>
+position=< 21487,  10785> velocity=<-2, -1>
+position=<-31711,  10792> velocity=< 3, -1>
+position=<-21085, -10497> velocity=< 2,  1>
+position=<-42360, -42432> velocity=< 4,  4>
+position=<-21090,  21434> velocity=< 2, -2>
+position=<-31739,  32074> velocity=< 3, -3>
+position=< 53417, -10502> velocity=<-5,  1>
+position=<-42364, -21149> velocity=< 4,  2>
+position=< 42767, -21147> velocity=<-4,  2>
+position=< 21502,  10784> velocity=<-2, -1>
+position=<-53016, -53077> velocity=< 5,  5>
+position=<-10401,  10787> velocity=< 1, -1>
+position=<-31715,  53373> velocity=< 3, -5>
+position=< 10869,  53364> velocity=<-1, -5>
+position=< 10848, -10499> velocity=<-1,  1>
+position=< 10880, -10497> velocity=<-1,  1>
+position=<-31749,  32074> velocity=< 3, -3>
+position=<-42388, -31788> velocity=< 4,  3>
+position=<-10440,  42719> velocity=< 1, -4>
+position=< 10857, -53082> velocity=<-1,  5>
+position=< 53461, -21147> velocity=<-5,  2>
+position=<-21063, -10499> velocity=< 2,  1>
+position=< 32124,  42728> velocity=<-3, -4>
+position=<-21102,  10788> velocity=< 2, -1>
+position=< 32179,  32079> velocity=<-3, -3>
+position=< 10837,  32075> velocity=<-1, -3>
+position=<-42383,  32077> velocity=< 4, -3>
+position=< 42769,  21429> velocity=<-4, -2>
+position=< 21495, -10497> velocity=<-2,  1>
+position=< 32151, -42436> velocity=<-3,  4>
+position=< 32129,  10784> velocity=<-3, -1>
+position=<-31750,  10793> velocity=< 3, -1>
+position=< 53449, -42432> velocity=<-5,  4>
+position=< 32128, -42437> velocity=<-3,  4>
+position=<-42377, -21144> velocity=< 4,  2>
+position=< 10833,  53373> velocity=<-1, -5>
+position=< 32143,  32083> velocity=<-3, -3>
+position=< 42816, -31792> velocity=<-4,  3>
+position=<-31727,  42728> velocity=< 3, -4>
+position=<-21103,  42719> velocity=< 2, -4>
+position=<-42368,  21438> velocity=< 4, -2>
+position=<-21098, -10500> velocity=< 2,  1>
+position=<-31735, -10506> velocity=< 3,  1>
+position=<-42391,  32074> velocity=< 4, -3>
+position=<-21095, -53081> velocity=< 2,  5>
+position=<-21079, -21147> velocity=< 2,  2>
+position=< 32151,  53366> velocity=<-3, -5>
+position=<-42396,  10785> velocity=< 4, -1>
+position=< 32119,  21434> velocity=<-3, -2>
+position=<-31716, -42432> velocity=< 3,  4>
+position=< 32162,  32081> velocity=<-3, -3>
+position=< 10845,  21430> velocity=<-1, -2>
+position=< 32119, -21149> velocity=<-3,  2>
+position=< 53461, -10504> velocity=<-5,  1>
+position=<-21074, -42438> velocity=< 2,  4>
+position=< 10873,  53372> velocity=<-1, -5>
+position=<-42380, -31792> velocity=< 4,  3>
+position=<-31751,  10788> velocity=< 3, -1>
+position=<-31735, -53086> velocity=< 3,  5>
+position=< 21499,  10788> velocity=<-2, -1>
+position=< 32147,  10784> velocity=<-3, -1>
+position=<-10409,  42721> velocity=< 1, -4>
+position=< 21492, -42435> velocity=<-2,  4>
+position=< 10885, -42434> velocity=<-1,  4>
+position=< 53409, -42433> velocity=<-5,  4>
+position=<-31699,  10784> velocity=< 3, -1>
+position=< 53459, -31787> velocity=<-5,  3>
+position=<-21093, -42433> velocity=< 2,  4>
+position=< 53436, -42432> velocity=<-5,  4>
+position=< 42764,  42727> velocity=<-4, -4>
+position=<-52982,  10793> velocity=< 5, -1>
+position=<-21061, -53077> velocity=< 2,  5>
+position=< 21525,  10784> velocity=<-2, -1>
+position=<-10401, -53083> velocity=< 1,  5>
+position=< 10833,  10793> velocity=<-1, -1>
+position=< 42767,  10793> velocity=<-4, -1>
+position=< 10869,  21429> velocity=<-1, -2>
+position=<-42370, -53082> velocity=< 4,  5>
+position=< 10881,  53372> velocity=<-1, -5>
+position=<-10461,  21429> velocity=< 1, -2>
+position=<-21080, -42432> velocity=< 2,  4>
+position=< 42817,  10784> velocity=<-4, -1>
+position=< 42805, -10501> velocity=<-4,  1>
+position=<-42371, -31796> velocity=< 4,  3>
+position=<-42388,  32079> velocity=< 4, -3>
+position=< 21490,  21436> velocity=<-2, -2>
+position=<-10421,  42726> velocity=< 1, -4>
+position=< 21492,  42722> velocity=<-2, -4>
+position=< 42799,  42728> velocity=<-4, -4>
+position=<-53025,  10787> velocity=< 5, -1>
+position=< 21474, -42441> velocity=<-2,  4>
+position=< 53433,  10792> velocity=<-5, -1>
+position=< 32130, -31796> velocity=<-3,  3>
+position=< 53438, -10506> velocity=<-5,  1>
+position=<-10445, -21146> velocity=< 1,  2>
+position=< 21518, -10505> velocity=<-2,  1>
+position=< 32151,  42722> velocity=<-3, -4>
+position=< 21514,  42723> velocity=<-2, -4>
+position=<-31739,  21433> velocity=< 3, -2>
+position=<-21094, -10506> velocity=< 2,  1>
+position=< 32129, -31792> velocity=<-3,  3>
+position=< 42824, -53084> velocity=<-4,  5>
+position=<-52999, -42435> velocity=< 5,  4>
+position=< 53409, -31794> velocity=<-5,  3>
+position=<-42353, -10504> velocity=< 4,  1>
+position=< 32132, -42432> velocity=<-3,  4>
+position=< 42780, -42436> velocity=<-4,  4>
+position=< 10888, -31796> velocity=<-1,  3>
+position=<-10421, -53077> velocity=< 1,  5>
+position=<-53033, -21150> velocity=< 5,  2>
+position=< 21494, -53085> velocity=<-2,  5>
+position=< 21533, -10506> velocity=<-2,  1>
+position=< 53421,  32080> velocity=<-5, -3>
+position=< 32159, -10501> velocity=<-3,  1>
+position=< 10881,  21436> velocity=<-1, -2>
+position=< 21493,  32081> velocity=<-2, -3>
+position=<-42363,  53364> velocity=< 4, -5>
+position=<-52993,  42727> velocity=< 5, -4>
+position=< 10841, -31792> velocity=<-1,  3>
+position=< 10871, -53083> velocity=<-1,  5>
+position=<-42379,  53369> velocity=< 4, -5>
+position=< 21518,  21430> velocity=<-2, -2>
+position=<-31727,  32078> velocity=< 3, -3>
+position=<-42361, -31796> velocity=< 4,  3>
+position=< 32123, -21142> velocity=<-3,  2>
+position=< 10856,  10784> velocity=<-1, -1>
+position=< 10853,  21430> velocity=<-1, -2>
+position=< 21498, -31787> velocity=<-2,  3>
+position=<-21098, -10506> velocity=< 2,  1>
+position=<-42388, -10501> velocity=< 4,  1>
+position=<-42395, -31796> velocity=< 4,  3>
+position=< 10870, -42436> velocity=<-1,  4>
+position=< 42824, -10501> velocity=<-4,  1>
+position=< 42800,  10784> velocity=<-4, -1>
diff --git a/package.yaml b/package.yaml
index c9d7cf1..2267f2e 100644
--- a/package.yaml
+++ b/package.yaml
@@ -24,6 +24,7 @@ dependencies:
 - containers
 - text
 - extra
+- matrix
 
 library:
   source-dirs: src
diff --git a/src/Day10.hs b/src/Day10.hs
index 6eb3e43..4f158e3 100644
--- a/src/Day10.hs
+++ b/src/Day10.hs
@@ -1,6 +1,49 @@
 module Day10 (main) where
 
+import Data.List (sortBy, groupBy)
+import Data.Ord (comparing)
+import Data.Function (on)
+import Data.Tuple.Extra ((***))
+import Data.Matrix (matrix, toLists)
+
+type Point = (Position, Velocity)
+type Position = (Int, Int) -- ( x,  y)
+type Velocity = (Int, Int) -- (dx, dy)
+
+stepPoint :: Point -> Point
+stepPoint ((x, y), (dx, dy)) = ((x + dx, y + dy), (dx, dy))
+
+parse :: String -> Point
+parse str =
+    let position = "(" ++ (take 14 . drop 10 $ str) ++ ")"
+        velocity = "(" ++ (take  6 . drop 36 $ str) ++ ")"
+    in  (read position, read velocity)
+
+alignedX :: Int -> [Point] -> Bool
+alignedX n =
+    any nearby . map (snd . unzip) . groupBy ((==) `on` fst) . sortBy (comparing fst) . fst . unzip
+    where nearby ys = length ys >= n && (maximum ys) - (minimum ys) < n
+
+toGrid :: [Point] -> String
+toGrid points =
+    let positions = fst . unzip $ points
+        minX = minimum . fst . unzip $ positions
+        minY = minimum . snd . unzip $ positions
+        maxX = maximum . fst . unzip $ positions
+        maxY = maximum . snd . unzip $ positions
+        isPoint (y, x) = if (x + minX - 1, y + minY - 1) `elem` positions then '#' else '.'
+        grid = matrix (maxY - minY + 1) (maxX - minX + 1) isPoint
+    in  unlines . toLists $ grid
+
+part1 :: Int -> [Point] -> (String, Int)
+part1 sec points =
+    if   alignedX 10 points
+    then (toGrid $ points, sec)
+    else part1 (sec + 1) $ map stepPoint points
+
 main :: IO ()
 main = do
-    input <- readFile "input/10.txt"
-    print input
\ No newline at end of file
+    input <- map parse . lines <$> readFile "input/10.txt"
+    let result = part1 0 input
+    putStrLn $ fst result
+    print $ snd result