diff --git a/2018/day18/day18.go b/2018/day18/day18.go
new file mode 100644
index 0000000..9c19f17
--- /dev/null
+++ b/2018/day18/day18.go
@@ -0,0 +1,202 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"time"
+)
+
+const (
+	DIR_N  = -1i
+	DIR_NE = 1 - 1i
+	DIR_E  = 1
+	DIR_SE = 1 + 1i
+	DIR_S  = 1i
+	DIR_SW = -1 + 1i
+	DIR_W  = -1
+	DIR_NW = -1 - 1i
+
+	CLEAR_SCREEN = "\033[H\033[2J"
+)
+
+var scan []byte
+var next []byte
+var prevScans [][]byte
+var width, height int
+
+func main() {
+	stdinToByteSlice()
+	part1()
+	part2()
+}
+
+func part1() {
+	printScan()
+	for i := 0; i < 10; i++ {
+		fmt.Print(CLEAR_SCREEN)
+		scan = tickToNext()
+		printScan()
+		time.Sleep(time.Millisecond * 250)
+	}
+	var ttlOpen, ttlTrees, ttlLmbr int
+	for i := range scan {
+		switch getByte(getPosFromInt(i)) {
+		case '.':
+			ttlOpen++
+		case '|':
+			ttlTrees++
+		case '#':
+			ttlLmbr++
+		}
+	}
+	_ = ttlOpen
+	fmt.Println("= Part 1 =")
+	fmt.Println(ttlTrees * ttlLmbr)
+}
+
+// 191080?
+func part2() {
+	var isDupe bool
+	var i int
+	target := 1000000000
+	for i = 0; i < target; i++ {
+		//fmt.Print(CLEAR_SCREEN, target)
+		next := tickToNext()
+		if isDupe, prevScans = checkDuplicateState(next, prevScans); isDupe {
+			i++
+			scan = next
+			break
+		}
+		prevScans = append(prevScans, next)
+		scan = next
+	}
+	// We need to find the state after `target` increments
+	scan = prevScans[(target-i)%len(prevScans)]
+	var ttlOpen, ttlTrees, ttlLmbr int
+	for i := range scan {
+		switch getByte(getPosFromInt(i)) {
+		case '.':
+			ttlOpen++
+		case '|':
+			ttlTrees++
+		case '#':
+			ttlLmbr++
+		}
+	}
+	_ = ttlOpen
+	fmt.Println("= Part 2 =")
+	fmt.Println(ttlTrees * ttlLmbr)
+}
+
+// checkDuplicateState returns the slice of prev that has all remaining available states
+func checkDuplicateState(s []byte, prev [][]byte) (bool, [][]byte) {
+	for i, v := range prev {
+		if areasAreEqual(s, v) {
+			return true, prev[i:]
+		}
+	}
+	return false, prev
+}
+
+func areasAreEqual(a1, a2 []byte) bool {
+	for i := range a1 {
+		if a1[i] != a2[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func tickToNext() []byte {
+	var ret []byte
+	for i := 0; i < len(scan); i++ {
+		c := getPosFromInt(i)
+		_, sTree, sLmbr := getSurroundingCounts(c)
+		b := getByte(c)
+		switch b {
+		case '.':
+			if sTree >= 3 {
+				ret = append(ret, '|')
+			} else {
+				ret = append(ret, '.')
+			}
+		case '|':
+			if sLmbr >= 3 {
+				ret = append(ret, '#')
+			} else {
+				ret = append(ret, '|')
+			}
+		case '#':
+			if sLmbr > 0 && sTree > 0 {
+				ret = append(ret, '#')
+			} else {
+				ret = append(ret, '.')
+			}
+		}
+	}
+	return ret
+}
+
+// getSurroundingCounts takes a pos and returns:
+//	Number of open areas
+//	Number of trees
+//  Number of lumberyards
+// Surrounding that spot
+func getSurroundingCounts(c complex64) (int, int, int) {
+	var sOpen, sTree, sLmbr int
+	for _, v := range []complex64{DIR_NW, DIR_N, DIR_NE, DIR_W, DIR_E, DIR_SW, DIR_S, DIR_SE} {
+		switch getByte(c + v) {
+		case '.':
+			sOpen++
+		case '|':
+			sTree++
+		case '#':
+			sLmbr++
+		}
+	}
+	return sOpen, sTree, sLmbr
+}
+
+func printScan() {
+	for i := 0; i < len(scan)/width; i++ {
+		fmt.Println(string(scan[i*width : (i+1)*width]))
+	}
+}
+
+// getByte pulls a byte from the given position in the scan
+func getByte(pos complex64) byte {
+	//idx := int(real(pos)) + int(imag(pos))*width
+	if int(real(pos)) < 0 || int(imag(pos)) < 0 || int(real(pos)) >= width || int(imag(pos)) >= height {
+		return 0
+	}
+	return scan[int(real(pos))+int(imag(pos))*width]
+}
+
+func getPosComplex(x, y int) complex64 {
+	return complex(float32(x), float32(y))
+}
+
+func getPosFromInt(i int) complex64 {
+	return complex(float32(i%width), float32(i/width))
+}
+
+func getIdxFromPos(pos complex64) int {
+	return int(real(pos)) + int(imag(pos))*width
+}
+
+func getCoordString(p complex64) string {
+	return fmt.Sprintf("(%d,%d [%d])", int(real(p)), int(imag(p)), getIdxFromPos(p))
+}
+
+func stdinToByteSlice() {
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		s := scanner.Bytes()
+		if width == 0 {
+			width = len(s)
+		}
+		scan = append(scan, s...)
+		height++
+	}
+}
diff --git a/2018/day18/input b/2018/day18/input
new file mode 100644
index 0000000..98cad1f
--- /dev/null
+++ b/2018/day18/input
@@ -0,0 +1,50 @@
+.#|#.##....#|....|.#.#.|||.#.|....||....|...|..#..
+..|#||.|#..|...|#|..#...|#...#..#..|.....||..#.|#.
+#|||#..||.....||.#................|..#.##|.#...#.|
+|#..#.|...##...#..#|#|#..|#.#...|....#..#...##....
+.###.........|.||#...#|.|#.||||#..|...||....#..#..
+###.|..|#|...|..||..##.....|..#.|.#.............|.
+..|.|.||.#....|...|....#|.........##||..#||..|.##.
+#||#|...#|..|.|.||#...#|...|#.......|...#.....|...
+....||.....|.|.....#...|.......|...|..|...|......|
+#......#..#|#|..|....#.|.|.#...#.#.|..#.|.....#.#.
+.|#...|...........#|.#....#.#...#.|..|...|....|.|.
+..||.#.|...||#|....#.#..||#..#...#|..#..|..#|.....
+|..|.|..#...|.....#.|..|#.||..#|.|.||#|#..|#...##|
+..|..|#......||##..|........#.|...#.|.|#.#...||..#
+#.|...#.||#..|.|..|..|.#....|.||....|.|....#....#.
+#||.|.#..#..|...#....##|#..#...#.#...|.#...#.....#
+#.|.##.|##..#.##|##........#.|...#...|..#|.#|#|...
+.|#|....|.#...#..|||.#.||..#||.||.|..#.|....|..##.
+|.#.||#|.##.|.||.....#...#.#..###|.#......||#|....
+.|.#..|#||......|##..##.#|..#|.|#.|.|#......|#.|#.
+#..|........|||..|###..|#..|||#.|.|.....#|..|...|#
+..####||#......|#||..###.|...|....#..|.#|.||....||
+|##.......|||..........|..||.#.|#.......##...|...|
+|.......#......####|#|....#....|......#.|#.###...#
+#|.#.|||...|..|.....#....|...|......|#|#|......||.
+...#.|......#..||||.#|.....|.|.|||.|.|.|#|.#...#.#
+#.#.##.|.#|.|...|...|...#|...#.|#..|..##.|....#..|
+|...#.......#....#....#.#....#.#|.|#||.|.|.|#...#.
+#..|.||..|.#..|.#.....#|##.|.|....|....||.......|.
+..||.#..|#|.###....#.#|..#|.#..........#...|...#|.
+|#||.|.#..|....|....#.#||#.|......#..|#.#.|||||#|.
+.|#.|#.##.....#.|.#.....|....|.#..#.#..|#.#.....|.
+#.||.#.......|..|......|#||.|..#....#...|...|...|.
+|.....#.|.....#||.....##...#.#...||.|..#........|.
+||#..|.##.#...........#..|..|.|..#....|...#..||.#.
+..||.##.##.|.||......#...|.#.#.#..#.#...##.#.|.#..
+.|.#......#|#||.|.#|......||.#.|.|..|....#...||...
+....|.##.....|#|####.#..#..#|.....|.#.#|......|...
+...#..|......#....|#.#...|...|.#.#.......#.#.##..#
+.|||#.||||...|..|#||.|.#|#||..|..#..|..|..#||.....
+.....|..#..|#|.||.#||.||......|||..|..#|.|##......
+.#...#|..#..|||..||.|..|.#.#.......||..|...|.|....
+.##.||..|..||.|.......#.|||.|.|..|.#.#..|.||.|#|||
+.|..##|..#.#|#|....|.#.#.#|#.#|.##|........###...#
+..#..|#|...#.........#.#.####..#.#..#..#||#|...#|#
+#.|...|.......|.#.#..#.|#..#|#|..#..|.....|..|...|
+.##.|..#.....|...#..|#..|.|.#..##.#.|..#.|..|.##..
+....|..|.|..||....|...|.....#..|.|.....|.#|......#
+...##.|#..#..|.#|.##....|.#...||#|.....#...##.#|..
+.|....##.....||...#.#.....#|#...#...#|.|..#.#.#.##
diff --git a/2018/day18/problem b/2018/day18/problem
new file mode 100644
index 0000000..26c93fe
--- /dev/null
+++ b/2018/day18/problem
@@ -0,0 +1,203 @@
+Advent of Code
+
+--- Day 18: Settlers of The North Pole ---
+
+   On the outskirts of the North Pole base construction project, many Elves are collecting lumber.
+
+   The lumber collection area is 50 acres by 50 acres; each acre can be either open ground (.), trees (|), or a
+   lumberyard (#). You take a scan of the area (your puzzle input).
+
+   Strange magic is at work here: each minute, the landscape looks entirely different. In exactly one minute, an
+   open acre can fill with trees, a wooded acre can be converted to a lumberyard, or a lumberyard can be cleared
+   to open ground (the lumber having been sent to other projects).
+
+   The change to each acre is based entirely on the contents of that acre as well as the number of open, wooded,
+   or lumberyard acres adjacent to it at the start of each minute. Here, "adjacent" means any of the eight acres
+   surrounding that acre. (Acres on the edges of the lumber collection area might have fewer than eight adjacent
+   acres; the missing acres aren't counted.)
+
+   In particular:
+
+     • An open acre will become filled with trees if three or more adjacent acres contained trees. Otherwise,
+       nothing happens.
+     • An acre filled with trees will become a lumberyard if three or more adjacent acres were lumberyards.
+       Otherwise, nothing happens.
+     • An acre containing a lumberyard will remain a lumberyard if it was adjacent to at least one other
+       lumberyard and at least one acre containing trees. Otherwise, it becomes open.
+
+   These changes happen across all acres simultaneously, each of them using the state of all acres at the
+   beginning of the minute and changing to their new form by the end of that same minute. Changes that happen
+   during the minute don't affect each other.
+
+   For example, suppose the lumber collection area is instead only 10 by 10 acres with this initial
+   configuration:
+
+ Initial state:
+ .#.#...|#.
+ .....#|##|
+ .|..|...#.
+ ..|#.....#
+ #.#|||#|#|
+ ...#.||...
+ .|....|...
+ ||...#|.#|
+ |.||||..|.
+ ...#.|..|.
+
+ After 1 minute:
+ .......##.
+ ......|###
+ .|..|...#.
+ ..|#||...#
+ ..##||.|#|
+ ...#||||..
+ ||...|||..
+ |||||.||.|
+ ||||||||||
+ ....||..|.
+
+ After 2 minutes:
+ .......#..
+ ......|#..
+ .|.|||....
+ ..##|||..#
+ ..###|||#|
+ ...#|||||.
+ |||||||||.
+ ||||||||||
+ ||||||||||
+ .|||||||||
+
+ After 3 minutes:
+ .......#..
+ ....|||#..
+ .|.||||...
+ ..###|||.#
+ ...##|||#|
+ .||##|||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+
+ After 4 minutes:
+ .....|.#..
+ ...||||#..
+ .|.#||||..
+ ..###||||#
+ ...###||#|
+ |||##|||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+
+ After 5 minutes:
+ ....|||#..
+ ...||||#..
+ .|.##||||.
+ ..####|||#
+ .|.###||#|
+ |||###||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+
+ After 6 minutes:
+ ...||||#..
+ ...||||#..
+ .|.###|||.
+ ..#.##|||#
+ |||#.##|#|
+ |||###||||
+ ||||#|||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+
+ After 7 minutes:
+ ...||||#..
+ ..||#|##..
+ .|.####||.
+ ||#..##||#
+ ||##.##|#|
+ |||####|||
+ |||###||||
+ ||||||||||
+ ||||||||||
+ ||||||||||
+
+ After 8 minutes:
+ ..||||##..
+ ..|#####..
+ |||#####|.
+ ||#...##|#
+ ||##..###|
+ ||##.###||
+ |||####|||
+ ||||#|||||
+ ||||||||||
+ ||||||||||
+
+ After 9 minutes:
+ ..||###...
+ .||#####..
+ ||##...##.
+ ||#....###
+ |##....##|
+ ||##..###|
+ ||######||
+ |||###||||
+ ||||||||||
+ ||||||||||
+
+ After 10 minutes:
+ .||##.....
+ ||###.....
+ ||##......
+ |##.....##
+ |##.....##
+ |##....##|
+ ||##.####|
+ ||#####|||
+ ||||#|||||
+ ||||||||||
+
+   After 10 minutes, there are 37 wooded acres and 31 lumberyards. Multiplying the number of wooded acres by the
+   number of lumberyards gives the total resource value after ten minutes: 37 * 31 = 1147.
+
+   What will the total resource value of the lumber collection area be after 10 minutes?
+
+   Your puzzle answer was 644640.
+
+--- Part Two ---
+
+   This important natural resource will need to last for at least thousands of years. Are the Elves collecting
+   this lumber sustainably?
+
+   What will the total resource value of the lumber collection area be after 1000000000 minutes?
+
+   Your puzzle answer was 191080.
+
+   Both parts of this puzzle are complete! They provide two gold stars: **
+
+References
+
+   Visible links
+   . https://adventofcode.com/
+   . https://adventofcode.com/2018/about
+   . https://adventofcode.com/2018/events
+   . https://adventofcode.com/2018/settings
+   . https://adventofcode.com/2018/auth/logout
+   . Advent of Code Supporter
+	https://adventofcode.com/2018/support
+   . https://adventofcode.com/2018
+   . https://adventofcode.com/2018
+   . https://adventofcode.com/2018/support
+   . https://adventofcode.com/2018/sponsors
+   . https://adventofcode.com/2018/leaderboard
+   . https://adventofcode.com/2018/stats
+   . https://adventofcode.com/2018/sponsors
+   . https://adventofcode.com/2018
+   . https://adventofcode.com/2018/day/18/input
diff --git a/2018/day18/testinput b/2018/day18/testinput
new file mode 100644
index 0000000..13d299d
--- /dev/null
+++ b/2018/day18/testinput
@@ -0,0 +1,10 @@
+.#.#...|#.
+.....#|##|
+.|..|...#.
+..|#.....#
+#.#|||#|#|
+...#.||...
+.|....|...
+||...#|.#|
+|.||||..|.
+...#.|..|.