diff --git a/aoc2015/input/day06.txt b/aoc2015/input/day06.txt
new file mode 100644
index 0000000..d6cfb3a
--- /dev/null
+++ b/aoc2015/input/day06.txt
@@ -0,0 +1,300 @@
+toggle 461,550 through 564,900
+turn off 370,39 through 425,839
+turn off 464,858 through 833,915
+turn off 812,389 through 865,874
+turn on 599,989 through 806,993
+turn on 376,415 through 768,548
+turn on 606,361 through 892,600
+turn off 448,208 through 645,684
+toggle 50,472 through 452,788
+toggle 205,417 through 703,826
+toggle 533,331 through 906,873
+toggle 857,493 through 989,970
+turn off 631,950 through 894,975
+turn off 387,19 through 720,700
+turn off 511,843 through 581,945
+toggle 514,557 through 662,883
+turn off 269,809 through 876,847
+turn off 149,517 through 716,777
+turn off 994,939 through 998,988
+toggle 467,662 through 555,957
+turn on 952,417 through 954,845
+turn on 565,226 through 944,880
+turn on 214,319 through 805,722
+toggle 532,276 through 636,847
+toggle 619,80 through 689,507
+turn on 390,706 through 884,722
+toggle 17,634 through 537,766
+toggle 706,440 through 834,441
+toggle 318,207 through 499,530
+toggle 698,185 through 830,343
+toggle 566,679 through 744,716
+toggle 347,482 through 959,482
+toggle 39,799 through 981,872
+turn on 583,543 through 846,710
+turn off 367,664 through 595,872
+turn on 805,439 through 964,995
+toggle 209,584 through 513,802
+turn off 106,497 through 266,770
+turn on 975,2 through 984,623
+turn off 316,684 through 369,876
+turn off 30,309 through 259,554
+turn off 399,680 through 861,942
+toggle 227,740 through 850,829
+turn on 386,603 through 552,879
+turn off 703,795 through 791,963
+turn off 573,803 through 996,878
+turn off 993,939 through 997,951
+turn on 809,221 through 869,723
+turn off 38,720 through 682,751
+turn off 318,732 through 720,976
+toggle 88,459 through 392,654
+turn off 865,654 through 911,956
+toggle 264,284 through 857,956
+turn off 281,776 through 610,797
+toggle 492,660 through 647,910
+turn off 879,703 through 925,981
+turn off 772,414 through 974,518
+turn on 694,41 through 755,96
+turn on 452,406 through 885,881
+turn off 107,905 through 497,910
+turn off 647,222 through 910,532
+turn on 679,40 through 845,358
+turn off 144,205 through 556,362
+turn on 871,804 through 962,878
+turn on 545,676 through 545,929
+turn off 316,716 through 413,941
+toggle 488,826 through 755,971
+toggle 957,832 through 976,992
+toggle 857,770 through 905,964
+toggle 319,198 through 787,673
+turn on 832,813 through 863,844
+turn on 818,296 through 818,681
+turn on 71,699 through 91,960
+turn off 838,578 through 967,928
+toggle 440,856 through 507,942
+toggle 121,970 through 151,974
+toggle 391,192 through 659,751
+turn on 78,210 through 681,419
+turn on 324,591 through 593,939
+toggle 159,366 through 249,760
+turn off 617,167 through 954,601
+toggle 484,607 through 733,657
+turn on 587,96 through 888,819
+turn off 680,984 through 941,991
+turn on 800,512 through 968,691
+turn off 123,588 through 853,603
+turn on 1,862 through 507,912
+turn on 699,839 through 973,878
+turn off 848,89 through 887,893
+toggle 344,353 through 462,403
+turn on 780,731 through 841,760
+toggle 693,973 through 847,984
+toggle 989,936 through 996,958
+toggle 168,475 through 206,963
+turn on 742,683 through 769,845
+toggle 768,116 through 987,396
+turn on 190,364 through 617,526
+turn off 470,266 through 530,839
+toggle 122,497 through 969,645
+turn off 492,432 through 827,790
+turn on 505,636 through 957,820
+turn on 295,476 through 698,958
+toggle 63,298 through 202,396
+turn on 157,315 through 412,939
+turn off 69,789 through 134,837
+turn off 678,335 through 896,541
+toggle 140,516 through 842,668
+turn off 697,585 through 712,668
+toggle 507,832 through 578,949
+turn on 678,279 through 886,621
+toggle 449,744 through 826,910
+turn off 835,354 through 921,741
+toggle 924,878 through 985,952
+turn on 666,503 through 922,905
+turn on 947,453 through 961,587
+toggle 525,190 through 795,654
+turn off 62,320 through 896,362
+turn on 21,458 through 972,536
+turn on 446,429 through 821,970
+toggle 376,423 through 805,455
+toggle 494,896 through 715,937
+turn on 583,270 through 667,482
+turn off 183,468 through 280,548
+toggle 623,289 through 750,524
+turn on 836,706 through 967,768
+turn on 419,569 through 912,908
+turn on 428,260 through 660,433
+turn off 683,627 through 916,816
+turn on 447,973 through 866,980
+turn on 688,607 through 938,990
+turn on 245,187 through 597,405
+turn off 558,843 through 841,942
+turn off 325,666 through 713,834
+toggle 672,606 through 814,935
+turn off 161,812 through 490,954
+turn on 950,362 through 985,898
+turn on 143,22 through 205,821
+turn on 89,762 through 607,790
+toggle 234,245 through 827,303
+turn on 65,599 through 764,997
+turn on 232,466 through 965,695
+turn on 739,122 through 975,590
+turn off 206,112 through 940,558
+toggle 690,365 through 988,552
+turn on 907,438 through 977,691
+turn off 838,809 through 944,869
+turn on 222,12 through 541,832
+toggle 337,66 through 669,812
+turn on 732,821 through 897,912
+toggle 182,862 through 638,996
+turn on 955,808 through 983,847
+toggle 346,227 through 841,696
+turn on 983,270 through 989,756
+turn off 874,849 through 876,905
+turn off 7,760 through 678,795
+toggle 973,977 through 995,983
+turn off 911,961 through 914,976
+turn on 913,557 through 952,722
+turn off 607,933 through 939,999
+turn on 226,604 through 517,622
+turn off 3,564 through 344,842
+toggle 340,578 through 428,610
+turn on 248,916 through 687,925
+toggle 650,185 through 955,965
+toggle 831,359 through 933,536
+turn off 544,614 through 896,953
+toggle 648,939 through 975,997
+turn on 464,269 through 710,521
+turn off 643,149 through 791,320
+turn off 875,549 through 972,643
+turn off 953,969 through 971,972
+turn off 236,474 through 772,591
+toggle 313,212 through 489,723
+toggle 896,829 through 897,837
+toggle 544,449 through 995,905
+turn off 278,645 through 977,876
+turn off 887,947 through 946,977
+turn on 342,861 through 725,935
+turn on 636,316 through 692,513
+toggle 857,470 through 950,528
+turn off 736,196 through 826,889
+turn on 17,878 through 850,987
+turn on 142,968 through 169,987
+turn on 46,470 through 912,853
+turn on 182,252 through 279,941
+toggle 261,143 through 969,657
+turn off 69,600 through 518,710
+turn on 372,379 through 779,386
+toggle 867,391 through 911,601
+turn off 174,287 through 900,536
+toggle 951,842 through 993,963
+turn off 626,733 through 985,827
+toggle 622,70 through 666,291
+turn off 980,671 through 985,835
+turn off 477,63 through 910,72
+turn off 779,39 through 940,142
+turn on 986,570 through 997,638
+toggle 842,805 through 943,985
+turn off 890,886 through 976,927
+turn off 893,172 through 897,619
+turn off 198,780 through 835,826
+toggle 202,209 through 219,291
+turn off 193,52 through 833,283
+toggle 414,427 through 987,972
+turn on 375,231 through 668,236
+turn off 646,598 through 869,663
+toggle 271,462 through 414,650
+turn off 679,121 through 845,467
+toggle 76,847 through 504,904
+turn off 15,617 through 509,810
+toggle 248,105 through 312,451
+turn off 126,546 through 922,879
+turn on 531,831 through 903,872
+toggle 602,431 through 892,792
+turn off 795,223 through 892,623
+toggle 167,721 through 533,929
+toggle 813,251 through 998,484
+toggle 64,640 through 752,942
+turn on 155,955 through 892,985
+turn on 251,329 through 996,497
+turn off 341,716 through 462,994
+toggle 760,127 through 829,189
+turn on 86,413 through 408,518
+toggle 340,102 through 918,558
+turn off 441,642 through 751,889
+turn on 785,292 through 845,325
+turn off 123,389 through 725,828
+turn on 905,73 through 983,270
+turn off 807,86 through 879,276
+toggle 500,866 through 864,916
+turn on 809,366 through 828,534
+toggle 219,356 through 720,617
+turn off 320,964 through 769,990
+turn off 903,167 through 936,631
+toggle 300,137 through 333,693
+toggle 5,675 through 755,848
+turn off 852,235 through 946,783
+toggle 355,556 through 941,664
+turn on 810,830 through 867,891
+turn off 509,869 through 667,903
+toggle 769,400 through 873,892
+turn on 553,614 through 810,729
+turn on 179,873 through 589,962
+turn off 466,866 through 768,926
+toggle 143,943 through 465,984
+toggle 182,380 through 569,552
+turn off 735,808 through 917,910
+turn on 731,802 through 910,847
+turn off 522,74 through 731,485
+turn on 444,127 through 566,996
+turn off 232,962 through 893,979
+turn off 231,492 through 790,976
+turn on 874,567 through 943,684
+toggle 911,840 through 990,932
+toggle 547,895 through 667,935
+turn off 93,294 through 648,636
+turn off 190,902 through 532,970
+turn off 451,530 through 704,613
+toggle 936,774 through 937,775
+turn off 116,843 through 533,934
+turn on 950,906 through 986,993
+turn on 910,51 through 945,989
+turn on 986,498 through 994,945
+turn off 125,324 through 433,704
+turn off 60,313 through 75,728
+turn on 899,494 through 940,947
+toggle 832,316 through 971,817
+toggle 994,983 through 998,984
+toggle 23,353 through 917,845
+toggle 174,799 through 658,859
+turn off 490,878 through 534,887
+turn off 623,963 through 917,975
+toggle 721,333 through 816,975
+toggle 589,687 through 890,921
+turn on 936,388 through 948,560
+turn off 485,17 through 655,610
+turn on 435,158 through 689,495
+turn on 192,934 through 734,936
+turn off 299,723 through 622,847
+toggle 484,160 through 812,942
+turn off 245,754 through 818,851
+turn on 298,419 through 824,634
+toggle 868,687 through 969,760
+toggle 131,250 through 685,426
+turn off 201,954 through 997,983
+turn on 353,910 through 832,961
+turn off 518,781 through 645,875
+turn off 866,97 through 924,784
+toggle 836,599 through 857,767
+turn on 80,957 through 776,968
+toggle 277,130 through 513,244
+turn off 62,266 through 854,434
+turn on 792,764 through 872,842
+turn off 160,949 through 273,989
+turn off 664,203 through 694,754
+toggle 491,615 through 998,836
+turn off 210,146 through 221,482
+turn off 209,780 through 572,894
+turn on 766,112 through 792,868
+turn on 222,12 through 856,241
diff --git a/aoc2015/src/day06.rs b/aoc2015/src/day06.rs
new file mode 100644
index 0000000..b134274
--- /dev/null
+++ b/aoc2015/src/day06.rs
@@ -0,0 +1,205 @@
+use std::error::Error;
+use std::str::FromStr;
+
+use aoc::err;
+use aoc::Result;
+
+const INPUT: &str = include_str!("../input/day06.txt");
+
+pub fn run() -> Result<()> {
+    println!("part 1: {}", part1(INPUT)?);
+    println!("part 2: {}", part2(INPUT)?);
+
+    Ok(())
+}
+
+fn part1(input: &str) -> Result<usize> {
+    let instructions = input
+        .lines()
+        .map(|line| {
+            line.trim_end()
+                .parse()
+                .map_err(|e| err!("couldn't parse instruction: {}", e))
+        })
+        .collect::<Result<Vec<Instruction>>>()?;
+
+    let mut grid: Vec<Vec<bool>> = vec![vec![false; 1000]; 1000];
+
+    for inst in instructions {
+        match inst.action {
+            Action::TurnOn => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = true;
+                    });
+            }
+            Action::TurnOff => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = false;
+                    });
+            }
+            Action::Toggle => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = !grid[x][y];
+                    });
+            }
+        }
+    }
+
+    Ok(grid
+        .iter()
+        .flat_map(|line| line.iter())
+        .filter(|v| **v)
+        .count())
+}
+
+fn part2(input: &str) -> Result<u64> {
+    let instructions = input
+        .lines()
+        .map(|line| {
+            line.trim_end()
+                .parse()
+                .map_err(|e| err!("couldn't parse instruction: {}", e))
+        })
+        .collect::<Result<Vec<Instruction>>>()?;
+
+    let mut grid: Vec<Vec<u64>> = vec![vec![0; 1000]; 1000];
+
+    for inst in instructions {
+        match inst.action {
+            Action::TurnOn => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = grid[x][y].saturating_add(1);
+                    });
+            }
+            Action::TurnOff => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = grid[x][y].saturating_sub(1);
+                    });
+            }
+            Action::Toggle => {
+                ((inst.horizontal.0)..=(inst.horizontal.1))
+                    .flat_map(|i| ((inst.vertical.0)..=(inst.vertical.1)).map(move |j| (i, j)))
+                    .for_each(|(x, y)| {
+                        grid[x][y] = grid[x][y].saturating_add(2);
+                    });
+            }
+        }
+    }
+
+    Ok(grid.iter().flat_map(|line| line.iter()).sum())
+}
+
+enum Action {
+    TurnOn,
+    TurnOff,
+    Toggle,
+}
+
+struct Instruction {
+    action: Action,
+    horizontal: (usize, usize),
+    vertical: (usize, usize),
+}
+
+impl FromStr for Instruction {
+    type Err = Box<dyn Error>;
+
+    fn from_str(s: &str) -> Result<Self> {
+        let mut space = s
+            .find(' ')
+            .ok_or_else(|| err!("couldn't parse instruction: {}", s))?;
+
+        let action = if &s[..space] == "toggle" {
+            Action::Toggle
+        } else if &s[..space] == "turn" {
+            space = s[(space + 1)..]
+                .find(' ')
+                .ok_or_else(|| err!("couldn't parse instruction: {}", s))?
+                + space
+                + 1;
+            if &s[..space] == "turn on" {
+                Action::TurnOn
+            } else if &s[..space] == "turn off" {
+                Action::TurnOff
+            } else {
+                return Err(err!("couldn't identify action: {}", &s[..space]));
+            }
+        } else {
+            return Err(err!("couldn't identify action: {}", s));
+        };
+        let s = &s[(space + 1)..];
+
+        let comma = s
+            .find(',')
+            .ok_or_else(|| err!("couldn't parse instruction: {}", s))?;
+        let x = s[..comma].parse()?;
+        let s = &s[(comma + 1)..];
+
+        let space = s
+            .find(' ')
+            .ok_or_else(|| err!("couldn't parse instruction: {}", s))?;
+        let y = s[..space].parse()?;
+        let s = &s[(space + 1)..];
+
+        let begin = (x, y);
+
+        let through = s
+            .find("through ")
+            .ok_or_else(|| err!("couldn't parse instruction: {}", s))?;
+        let s = &s[(through + 8)..];
+
+        let comma = s
+            .find(',')
+            .ok_or_else(|| err!("couldn't parse instruction: {}", s))?;
+        let x = s[..comma].parse()?;
+        let s = &s[(comma + 1)..];
+
+        let y = s.parse()?;
+
+        let end = (x, y);
+
+        Ok(Instruction {
+            action,
+            horizontal: (begin.0, end.0),
+            vertical: (begin.1, end.1),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_provided() {
+        assert_eq!(part1("turn on 0,0 through 999,999").unwrap(), 1_000_000);
+        assert_eq!(part1("toggle 0,0 through 999,0").unwrap(), 1_000);
+        assert_eq!(part1("turn off 499,499 through 500,500").unwrap(), 0);
+    }
+
+    #[test]
+    fn part1_real() {
+        assert_eq!(part1(INPUT).unwrap(), 543903);
+    }
+
+    #[test]
+    fn part2_provided() {
+        assert_eq!(part2("turn on 0,0 through 0,0").unwrap(), 1);
+        assert_eq!(part2("toggle 0,0 through 999,999").unwrap(), 2_000_000);
+    }
+
+    #[test]
+    fn part2_real() {
+        assert_eq!(part2(INPUT).unwrap(), 14687245);
+    }
+}
diff --git a/aoc2015/src/lib.rs b/aoc2015/src/lib.rs
index f290640..d945a75 100644
--- a/aoc2015/src/lib.rs
+++ b/aoc2015/src/lib.rs
@@ -3,3 +3,4 @@ pub mod day02;
 pub mod day03;
 pub mod day04;
 pub mod day05;
+pub mod day06;
diff --git a/aoc2015/src/main.rs b/aoc2015/src/main.rs
index fbc68a0..9318e18 100644
--- a/aoc2015/src/main.rs
+++ b/aoc2015/src/main.rs
@@ -5,9 +5,17 @@ use aoc2015::day02;
 use aoc2015::day03;
 use aoc2015::day04;
 use aoc2015::day05;
+use aoc2015::day06;
 
 fn main() -> Result<()> {
-    let days: &[fn() -> Result<()>] = &[day01::run, day02::run, day03::run, day04::run, day05::run];
+    let days: &[fn() -> Result<()>] = &[
+        day01::run,
+        day02::run,
+        day03::run,
+        day04::run,
+        day05::run,
+        day06::run,
+    ];
 
     aoc::run(days)
 }