diff --git a/day02.py b/day02.py
new file mode 100644
index 0000000..ca86131
--- /dev/null
+++ b/day02.py
@@ -0,0 +1,47 @@
+from lib import format_main
+from itertools import product
+from operator import mul, add
+
+def primitive(operator):
+    def opcode(program, i):
+        val = lambda x: program[program[x]]
+        program[program[i+3]] = operator(val(i+1), val(i+2))
+        return i+4
+    return opcode
+
+opcodes = {1  : primitive(add),
+           2  : primitive(mul),
+           99 : lambda p, i: len(p)
+          }
+
+def interpret(program):
+    i = 0
+    while i < len(program):
+        op = program[i]
+        i = opcodes[op](program, i)
+    return program
+
+
+
+def preproc(puzzle_input):
+    program = list(map(int, puzzle_input.split(',')))
+    init_prog = lambda a,b: program[:1] + [a, b] + program[3:]
+    return init_prog
+
+
+def partI(init_prog):
+    end_state = interpret(init_prog(12, 2))
+    return end_state[0]
+
+def partII(init_prog):
+    target = 19690720
+    space = 2 * list(range(100))
+    for noun, verb in product(space, space):
+        memory = init_prog(noun, verb)
+        end_state = interpret(memory)
+        if end_state[0] == target:
+            break
+
+    return 100*noun + verb
+
+import solver
diff --git a/day03.py b/day03.py
new file mode 100644
index 0000000..b05468e
--- /dev/null
+++ b/day03.py
@@ -0,0 +1,80 @@
+up    = lambda v: (v[0], v[1] + 1)
+down  = lambda v: (v[0], v[1] - 1)
+left  = lambda v: (v[0] - 1, v[1])
+right = lambda v: (v[0] + 1, v[1])
+
+moves = {'U' : up,
+         'D' : down,
+         'L' : left,
+         'R' : right
+        }
+
+def memoize(f):
+    cache = dict()
+    def memf(path):
+        if path not in cache:
+            cache[path] = f(path)
+        return cache[path]
+    return memf
+
+def iterate(f, x, N):
+    for i in range(N):
+        yield x
+        x = f(x)
+
+@memoize
+def lines(path):
+    pos = (0, 0)
+    r = []
+    for move in path.split(','):
+        dir, steps = move[0], int(move[1:])
+        line = list(iterate(moves[dir], pos, steps+1))
+        r.append(line)
+        pos = line[-1]
+    return r
+
+def coordinates(path, corners=True):
+    return sum((line[1:len(line) - 1 + corners]
+                for line in lines(path)), [])
+
+def crossings(*paths):
+    return set.intersection(*(set(coordinates(path, corners=False))
+                             for path in paths))
+
+def min_crossing(path1, path2, f):
+    return min(f(v) for v in crossings(path1, path2))
+
+def preproc(puzzle_input):
+    return puzzle_input.split()
+
+def partI(paths):
+    key = lambda v: abs(v[0]) + abs(v[1])
+
+    path1, path2 = paths
+    return min_crossing(path1, path2, key)
+
+def partII(paths):
+    path1, path2 = paths
+    def key(c1, c2):
+        r = lambda v: c1.index(v) + c2.index(v) + 2
+        return r
+
+    def min_steps(p1, p2):
+        c1, c2 = coordinates(p1), coordinates(p2)
+        return min_crossing(p1, p2, key(c1, c2))
+
+    return min_steps(path1, path2)
+
+import solver
+
+tests = solver.Tests()
+tests.add("R75,D30,R83,U83,L12,D49,R71,U7,L72\n" +
+          "U62,R66,U55,R34,D71,R55,D58,R83",
+         partI=159,
+         partII=610)
+
+tests.add("R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51\n" +
+          "U98,R91,D20,R16,D67,R40,U7,R15,U6,R7",
+         partI=135,
+         partII=410)
+
diff --git a/day04.py b/day04.py
new file mode 100644
index 0000000..9f785b3
--- /dev/null
+++ b/day04.py
@@ -0,0 +1,26 @@
+
+
+def preproc(puzzle_input):
+    space = tuple(map(int, puzzle_input.split('-')))
+    cands = []
+    for i in range(*space):
+        digs = str(i)
+
+        if sorted(digs) != list(digs):
+            continue
+        if max(digs.count(d) for d in set(digs)) < 2:
+            continue
+        cands.append(i)
+    return cands 
+
+def partI(cands):
+    return len(cands)
+
+def partII(cands):
+    c = 0
+    for i in cands:
+        digs = str(i)
+        if 2 in [digs.count(d) for d in set(digs)]:
+            c += 1
+    return c
+
diff --git a/day05.py b/day05.py
new file mode 100644
index 0000000..27f676f
--- /dev/null
+++ b/day05.py
@@ -0,0 +1,11 @@
+from intcode import Interpreter, SingletonIO
+
+def preproc(puzzle_input):
+    return list(map(int, puzzle_input.split(',')))
+
+def partI(program):
+    return Interpreter(program, SingletonIO).run(1)
+
+def partII(program):
+    return Interpreter(program, SingletonIO).run(5)
+
diff --git a/day06.py b/day06.py
new file mode 100644
index 0000000..98afb87
--- /dev/null
+++ b/day06.py
@@ -0,0 +1,44 @@
+from lib import Graph
+
+def preproc(puzzle_input):
+    graph = Graph()
+    for line in puzzle_input.split('\n'):
+        sun, planet = line.split(')')
+        graph.add_edge(sun, planet)
+    return graph
+
+def partI(graph):
+    return sum(w for node, w in graph.min_paths("COM").items())
+
+def partII(graph):
+    return graph.min_path("SAN", "YOU") - 2
+
+import solver
+
+tests = solver.Tests()
+tests.add("""COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L""", partI=42)
+
+tests.add("""COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L
+K)YOU
+I)SAN""", partII=4)
+
diff --git a/day07.py b/day07.py
new file mode 100644
index 0000000..b823eff
--- /dev/null
+++ b/day07.py
@@ -0,0 +1,72 @@
+from lib import format_main
+from intcode import Interpreter, makeIO, Singleton
+from itertools import permutations
+
+stack_size = 5
+fst_amp_input = 0
+
+IO = makeIO(list, Singleton)
+
+def preproc(puzzle_input):
+    program = list(map(int, puzzle_input.split(',')))
+    amp = lambda : Interpreter(program, IO)
+    return amp
+
+
+
+def partI(amp):
+    phase_range = range(stack_size)
+    best = 0 
+
+    for perm in permutations(phase_range):
+        amp_in = fst_amp_input
+        for phase in perm:
+            amp_in = amp().run([phase, amp_in])
+        best = max(amp_in, best)
+    return best
+   
+def partII(amp):
+    phase_range = range(5, 10)
+    best = 0 
+
+    for perm in permutations(phase_range):
+        amps = [amp() for _ in range(stack_size)]
+        for p, a in zip(perm, amps):
+            a.write([p])
+            next(a)
+
+        amp_in = fst_amp_input
+        while True:
+            try:
+                for a in amps:
+                    a.write([amp_in])
+                    amp_in = next(a)
+            except StopIteration:
+                break
+        best = max(amp_in, best)
+    
+    return best
+
+import solver
+
+tests = solver.Tests()
+
+tests.add(
+    "3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0", partI=43210)
+
+tests.add(
+    "3,23,3,24,1002,24,10,24,1002,23,-1,23," +
+    "101,5,23,23,1,24,23,23,4,23,99,0,0", partI=54321)
+
+tests.add(
+    "3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33," +
+    "1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0", partI=65210)
+
+tests.add(
+    "3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26," +
+    "27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5", partII=139629729)
+
+tests.add(
+    "3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54," +
+    "-5,54,1105,1,12,1,53,54,53,1008,54,0,55,1001,55,1,55,2,53,55,53,4," +
+    "53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10", partII=18216)
diff --git a/day08.py b/day08.py
new file mode 100644
index 0000000..b12bec1
--- /dev/null
+++ b/day08.py
@@ -0,0 +1,48 @@
+
+ZERO, ONE, TWO = "012"
+
+BLACK = 0
+WHITE = 1
+
+color = {WHITE : u"\u2B1C",
+         BLACK : u"\u2B1B"
+        }
+
+
+class Image:
+    def __init__(self, data, w, h):
+        self.data = data
+        self.w    = w
+        self.h    = h
+
+    def layers(self):
+        w, h = self.w, self.h
+        return (self.data[i:i+w*h] for i in range(0, len(self.data), w*h))
+
+    def image(self):
+        final = str()
+        for stack in zip(*self.layers()):
+            final += (''.join(stack).replace(TWO, "") + TWO)[0]
+        return final
+
+    def __repr__(self):
+        w, image = self.w, self.image()
+        return '\n'.join(image[i:i+w] for i in range(0, len(image), w))
+
+    def __str__(self):
+        return repr(self).replace(ZERO, color[BLACK]).replace(ONE, color[WHITE])
+
+
+
+def preproc(puzzle_input):
+    w, h = 25, 6
+    data = puzzle_input.replace('\n', '')
+    return Image(data, w, h)
+
+def partI(image):
+    layer = min(image.layers(), key=lambda ly: ly.count(ZERO))
+    return layer.count(ONE) * layer.count(TWO)
+
+def partII(image):
+    return '\n' + str(image)
+
diff --git a/day09.py b/day09.py
new file mode 100644
index 0000000..40b30c1
--- /dev/null
+++ b/day09.py
@@ -0,0 +1,15 @@
+from intcode import Interpreter, SingletonIO
+
+def preproc(puzzle_input):
+    return list(map(int, puzzle_input.split(',')))
+
+def partI(program):
+    return Interpreter(program, SingletonIO).run(1)
+
+def partII(program):
+    return Interpreter(program, SingletonIO).run(2)
+
+import solver
+
+tests = solver.Tests()
+tests.add("104,1125899906842624,99", partI=1125899906842624)
diff --git a/day10.py b/day10.py
new file mode 100644
index 0000000..4f1abd5
--- /dev/null
+++ b/day10.py
@@ -0,0 +1,146 @@
+from fractions import gcd, Fraction
+from itertools import product
+from functools import total_ordering
+from collections import defaultdict
+
+ASTEROID = '#'
+
+def zrange(x, y, step):
+    if x == y == step == 0:
+        def yzero():
+            while True:
+                yield 0
+        return yzero()
+    return range(x, y, step)
+
+def angle(v):
+        if v.x == 0:
+            return (2 * int(v.y > 0), 0)
+        halve = 1 if v.x > 0 else 3
+        return (halve, Fraction(v.y, v.x))
+
+def rebase(base, vectors):
+    return (v - base for v in vectors if v != base)
+
+@total_ordering
+class Vector:
+    def __init__(self, x, y):
+        self.x = x
+        self.y = y
+    def __add__(self, other):
+        return Vector(self.x + other.x, self.y + other.y)
+    def __sub__(self, other):
+        return self + Vector(-other.x, -other.y)
+    def __eq__(self, other):
+        return self.x == other.x and self.y == other.y
+    def __lt__(self, other):
+        return (self.x**2 + self.y**2) < (other.x**2 + other.y**2)
+    def __str__(self):
+        return str((self.x, self.y))
+    def __repr__(self):
+        return str(self)
+
+class Map:
+    def __init__(self, map):
+        self.map = map
+
+    def __getitem__(self, v):
+        return self.map[v.y][v.x]
+
+    def __str__(self):
+        return '\n'.join(self.map)
+
+    def is_asteroid(self, v):
+        return self[v] == ASTEROID
+
+    def vectors(self):
+        X, Y = len(self.map[0]), len(self.map)
+        return (Vector(x, y) for x, y in product(range(X), range(Y)))
+
+    def asteroid_vectors(self):
+        return filter(lambda v: self.is_asteroid(v), self.vectors())
+
+    def num_in_sight(self, v):
+        vs = rebase(v, self.asteroid_vectors())
+        return len(set(map(angle, vs)))
+
+    def best(self):
+        return max((self.num_in_sight(v), v) for v in self.asteroid_vectors())
+
+    def vaporize_seq(self, base):
+        vs = rebase(base, self.asteroid_vectors())
+        angles = defaultdict(list)
+        for v in vs:
+            angles[angle(v)].append(v)
+        for ang in angles.keys():
+            angles[ang].sort()
+        r = []
+        for i in range(max(map(len, angles.values()))):
+            r += [angles[ang][i] + base
+                  for ang in sorted(angles.keys()) if i < len(angles[ang])]
+        return r
+
+def preproc(puzzle_input):
+    asteroid_map = Map(puzzle_input.split())
+    score, asteroid = asteroid_map.best()
+    return asteroid_map, asteroid, score
+
+def partI(packed):
+    _, _, score = packed
+    return score
+
+def partII(packed):
+    asteroid_map, asteroid, _ = packed
+    v = asteroid_map.vaporize_seq(asteroid)[199]
+    return 100*v.x + v.y
+
+import solver
+
+tests = solver.Tests()
+
+map1 = \
+""".#..#
+.....
+#####
+....#
+...##"""
+
+map2 = \
+"""#.#...#.#.
+.###....#.
+.#....#...
+##.#.#.#.#
+....#.#.#.
+.##..###.#
+..#...##..
+..##....##
+......#...
+.####.###.
+"""
+
+map3 = \
+""".#..##.###...#######
+##.############..##.
+.#.######.########.#
+.###.#######.####.#.
+#####.##.#.##.###.##
+..#####..#.#########
+####################
+#.####....###.#.#.##
+##.#################
+#####.##.###..####..
+..######..##.#######
+####.##.####...##..#
+.#####..#.######.###
+##...#.##########...
+#.##########.#######
+.####.#.###.###.#.##
+....##.##.###..#####
+.#.#.###########.###
+#.#.#.#####.####.###
+###.##.####.##.#..##
+"""
+
+tests.add(map1, partI=8)
+tests.add(map2, partI=35)
+tests.add(map3, partI=210, partII=802)
diff --git a/day11.py b/day11.py
new file mode 100644
index 0000000..c433cb9
--- /dev/null
+++ b/day11.py
@@ -0,0 +1,85 @@
+from advent import read_input
+from intcode import Interpreter
+from collections import defaultdict
+
+BLACK = 0
+WHITE = 1
+
+color = {WHITE : u"\u2B1C",
+         BLACK : u"\u2B1B"
+        }
+
+UP    = (0, 1)
+LEFT  = 0
+RIGHT = 1
+
+def rotate(v, dir):
+    return (-dir) * v[1], dir * v[0]
+
+def left(v):
+    return rotate(v, 1)
+
+def right(v):
+    return rotate(v, -1)
+
+def add(v1, v2):
+    return v1[0] + v2[0], v1[1] + v2[1]
+
+class Canvas(defaultdict):
+    def __init__(self, color):
+        self.color = color
+        super(Canvas, self).__init__(int)
+
+    def __str__(self):
+        xs, ys = zip(*self.keys())
+        return '\n'.join(''.join(self.color[self[(x, y)]]
+                         for x in range(min(xs), max(xs)+1))
+                            for y in range(max(ys), min(ys)-1, -1))
+
+    def __repr__(self):
+        return unicode(self).encode("utf-8")
+
+
+class robotIO:
+    def __init__(self, canvas=Canvas(color)):
+        self.canvas = canvas
+        self.dir    = UP
+        self.pos    = 0, 0
+        self.paint  = True
+
+    def pop_input(self):
+        return self.canvas[self.pos]
+
+    def append_output(self, x):
+        if self.paint:
+            self.canvas[self.pos] = x
+        else:
+            self.dir = left(self.dir) if x == LEFT else right(self.dir)
+            self.pos = add(self.pos, self.dir)
+        self.paint = not self.paint
+
+    def flush(self):
+        return self.canvas
+
+class Robot:
+    def __init__(self, program, canvas=Canvas(color)):
+        self.canvas = canvas
+        self.program = program
+
+    def paint(self):
+        comp = Interpreter(self.program, robotIO)
+        comp.IO.canvas = self.canvas
+        return comp.run()
+
+def preproc(puzzle_input):
+    return list(map(int, puzzle_input.split(',')))
+
+def partI(program):
+    canvas = Robot(program).paint()
+    return len(canvas)
+
+def partII(program):
+    canvas = Canvas(color)
+    canvas[(0, 0)] = WHITE
+    canvas = Robot(program, canvas).paint()
+    return '\n' + str(canvas)