diff --git a/day08/default.nix b/day08/default.nix
new file mode 100644
index 0000000..280713f
--- /dev/null
+++ b/day08/default.nix
@@ -0,0 +1,113 @@
+{ pkgs, lib }:
+
+with lib;
+
+let
+  calculateTreeVisibilityForLine = line: let
+    updateState = { currentMax ? (-1), trees ? [] }: tree:
+      if tree > currentMax then { currentMax = tree; trees = trees ++ [true]; }
+                           else { inherit currentMax; trees = trees ++ [false]; };
+    forwards = (foldl updateState { } line).trees;
+    backwards = reverseList (foldr (flip updateState) { } line).trees;
+  in zipListsWith or forwards backwards;
+
+  transpose = grid: 
+    genList (n: map ((flip elemAt) n) grid) (length grid);
+
+  combineGridsWith = f: grid1: grid2: let
+    height = length grid1;
+    width = length (elemAt grid1 0);
+    elemAt' = row: col: grid: elemAt (elemAt grid row) col;
+    generator = row: col: f (elemAt' row col grid1) (elemAt' row col grid2);
+  in genList (row: genList (col: generator row col) width) height;
+
+  trees = pipe ./input.txt [
+    fileContents
+    (splitString "\n")
+    (map (splitString ""))
+    (map tail)
+    (map init)
+    (map (map toInt))
+  ];
+
+  treeVisibleGrid = pipe trees [
+    (lines: { horizontal = lines; vertical = transpose lines; })
+    (mapAttrs (_: map calculateTreeVisibilityForLine))
+    ({horizontal, vertical}: { inherit horizontal; vertical = transpose vertical; })
+    ({horizontal, vertical}: combineGridsWith or horizontal vertical)
+  ];
+
+  visualization = let
+    genColor = name: command: builtins.readFile
+      (pkgs.runCommand name {
+        buildInputs = [ pkgs.ncurses ];
+      } "tput ${command} > $out");
+    red = genColor "red" "setaf 1";
+    green = genColor "green" "setaf 2";
+    clear = genColor "clear" "sgr0";
+
+    greenRedTree = visible: tree:
+      if visible then "${green}${tree}${clear}"
+                 else "${red}${tree}${clear}";
+
+  in pipe trees [
+    (map (map toString))
+    (combineGridsWith greenRedTree treeVisibleGrid)
+    (map (concatStringsSep ""))
+    (concatStringsSep "\n")
+  ];
+
+  answer1 = pipe treeVisibleGrid [
+    (map (count id))
+    (foldr add 0)
+    toString
+  ];
+
+  countUntil = stopPred: xs:
+    if xs == [] then 0
+    else if stopPred (head xs) then 1
+    else 1 + (countUntil stopPred (tail xs));
+
+  visibleDistanceBackwards = line: let
+    measure = trees: size: let
+      newTree = {
+        inherit size;
+        viewDistance = countUntil (x: x.size >= size) trees;
+      };
+    in [newTree] ++ trees;
+  in pipe line [
+    (foldl measure [])
+    (map (x: x.viewDistance))
+    reverseList
+  ];
+
+  visibleDistanceHorizontal = line: let
+    backwards = visibleDistanceBackwards line;
+    forwards = pipe line [
+      reverseList
+      visibleDistanceBackwards 
+      reverseList
+    ];
+  in zipListsWith (x: y: x * y) forwards backwards;
+
+  answer2 = pipe trees [
+    (lines: { horizontal = lines; vertical = transpose lines; })
+    (mapAttrs (_: map visibleDistanceHorizontal))
+    ({horizontal, vertical}: { inherit horizontal; vertical = transpose vertical; })
+    ({horizontal, vertical}: combineGridsWith (x: y: x * y) horizontal vertical)
+    (map (foldr max 0))
+    (foldr max 0)
+    toString
+  ];
+
+in pkgs.writeText "answers" ''
+  Task1:
+    ${answer1}
+
+  Visualization:
+
+  ${visualization}
+
+  Task2:
+    ${answer2}
+''
diff --git a/day08/input.txt b/day08/input.txt
new file mode 100644
index 0000000..fb28721
--- /dev/null
+++ b/day08/input.txt
@@ -0,0 +1,99 @@
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diff --git a/day08/test.txt b/day08/test.txt
new file mode 100644
index 0000000..16d6fbd
--- /dev/null
+++ b/day08/test.txt
@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390
diff --git a/flake.nix b/flake.nix
index 7b48120..3b851c1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,6 +13,7 @@
       day05 = pkgs.callPackage ./day05 { };
       day06 = pkgs.callPackage ./day06 { };
       day07 = pkgs.callPackage ./day07 { };
+      day08 = pkgs.callPackage ./day08 { };
     };
   };
 }