diff --git a/day8/input b/day8/input
new file mode 100644
index 0000000..db567c3
--- /dev/null
+++ b/day8/input
@@ -0,0 +1,50 @@
+..f........................8......................
+G............8..u.................................
+........G...p.....................................
+......d.....................n.....................
+..................................................
+.....................................K............
+..................F...8.n...B.K...................
+....b.........8..u................................
+...............F.p.......B.............4.....5....
+....f..d..U.........................c.............
+...........U.....d.n.u.0................5.........
+...Y.......f..........................5...........
+..........................u.....d.....e.........4.
+..F...p.............v........n....................
+....s.............0...............................
+...US.s....g.....D..........................4.....
+......wG...............S..........................
+.............................B.....e..............
+.........w.........................A..............
+.............9w.g..........................4......
+U....9..g.....v.....P....D.....f.K................
+.s.............0..9........pP..........5..........
+..9s...................P..........................
+.............b..................0.....A..2....e...
+....................b.....V..v....................
+.......7........B......................A..........
+..................D6...V....q.....................
+...v............D....PV...........................
+.........Y...........g.......................e..y.
+.......SW......V..7....................c..........
+.......bY7.....................N........A.........
+.....................q.N..........y...............
+........................N.........c...............
+..................................................
+.........C..7..................q........2.........
+............................N...q.................
+...W......C3...Q................a1.........y......
+.......W.......................3......2...........
+........3...........6.............1...............
+....3............C.1....................k.........
+E..................................a.....c........
+.............................................w....
+..S.......................Q..........2......k.....
+......................C....6.......Q......ak......
+..................................................
+.................E.............a1............y....
+W..........E......................................
+......E...........6...........Q...................
+...........................k......................
+..................................................
diff --git a/day8/main.go b/day8/main.go
new file mode 100644
index 0000000..f2f923e
--- /dev/null
+++ b/day8/main.go
@@ -0,0 +1,122 @@
+package main
+
+import (
+	"fmt"
+
+	"git.mstar.dev/mstar/aoc24/util"
+	"git.mstar.dev/mstar/goutils/sliceutils"
+)
+
+type Vec struct {
+	X, Y int
+}
+
+type Sender struct {
+	Pos  Vec
+	Type rune
+}
+
+// Vec from v to o
+func (v Vec) Diff(o Vec) Vec {
+	return Vec{o.X - v.X, o.Y - v.Y}
+}
+
+func (v Vec) Add(o Vec) Vec {
+	return Vec{v.X + o.X, v.Y + o.Y}
+}
+
+func (v Vec) Invert() Vec {
+	return Vec{v.X * -1, v.Y * -1}
+}
+
+func getSendersFromLines(lines []string) (senderMap map[rune][]Sender) {
+	senderMap = map[rune][]Sender{}
+	for iy, line := range lines {
+		for ix, char := range line {
+			if char != '.' {
+				senderMap[char] = append(senderMap[char], Sender{Vec{ix, iy}, char})
+			}
+		}
+	}
+	return
+}
+
+func visualise(allSenders map[rune][]Sender, signals []Vec, size Vec) string {
+	area := [][]rune{}
+	for range size.Y {
+		axis := []rune{}
+		for range size.X {
+			axis = append(axis, '.')
+		}
+		area = append(area, axis)
+	}
+
+	for _, senders := range allSenders {
+		for _, sender := range senders {
+			area[sender.Pos.Y][sender.Pos.X] = sender.Type
+		}
+	}
+	for _, signal := range signals {
+		area[signal.Y][signal.X] = '#'
+	}
+	lines := sliceutils.Map(area, func(t []rune) string { return string(t) })
+	return sliceutils.Compact(lines, func(acc, next string) string { return acc + "\n" + next })
+}
+
+func posInBounds(pos, bounds Vec) bool {
+	return pos.X < bounds.X && pos.X >= 0 && pos.Y < bounds.Y && pos.Y >= 0
+}
+
+func generateSignalPositions2(sender1, sender2 Sender, size Vec) (positions []Vec) {
+	diff := sender1.Pos.Diff(sender2.Pos)
+	invertedDiff := diff.Invert()
+	positions = append(positions, sender1.Pos, sender2.Pos)
+	for nextPost := sender1.Pos.Add(diff); posInBounds(nextPost, size); nextPost = nextPost.Add(diff) {
+		positions = append(positions, nextPost)
+	}
+	for nextPost := sender1.Pos.Add(invertedDiff); posInBounds(nextPost, size); nextPost = nextPost.Add(invertedDiff) {
+		positions = append(positions, nextPost)
+	}
+	return
+}
+
+func main() {
+	inputLines := util.FileContentToNonEmptyLines(util.LoadFileFromArgs())
+	allSenders := getSendersFromLines(inputLines)
+	size := Vec{len(inputLines[0]), len(inputLines)}
+
+	signalPositions := []Vec{}
+	for _, senders := range allSenders {
+		passedSenders := []Sender{senders[0]}
+		for _, sender := range senders[1:] {
+			for _, checked := range passedSenders {
+				diff := sender.Pos.Diff(checked.Pos)
+				signalPositions = append(signalPositions, sender.Pos.Add(diff.Invert()))
+				signalPositions = append(signalPositions, checked.Pos.Add(diff))
+			}
+			passedSenders = append(passedSenders, sender)
+		}
+	}
+	signalPositions = sliceutils.Filter(signalPositions, func(t Vec) bool {
+		return t.X < size.X && t.X >= 0 && t.Y < size.Y && t.Y >= 0
+	})
+	signalPositions = sliceutils.RemoveDuplicate(signalPositions)
+	// fmt.Printf("Size: %v\n", size)
+
+	fmt.Printf("Task 1: %d\n", len(signalPositions))
+	signals2 := []Vec{}
+	for _, senders := range allSenders {
+		passedSenders := []Sender{senders[0]}
+		for _, sender := range senders[1:] {
+			for _, checked := range passedSenders {
+				signals2 = append(signals2, generateSignalPositions2(sender, checked, size)...)
+			}
+			passedSenders = append(passedSenders, sender)
+		}
+	}
+	signals2 = sliceutils.Filter(signals2, func(t Vec) bool {
+		return t.X < size.X && t.X >= 0 && t.Y < size.Y && t.Y >= 0
+	})
+	signals2 = sliceutils.RemoveDuplicate(signals2)
+	fmt.Printf("Task 2: %d\n", len(signals2))
+}
diff --git a/day8/sample b/day8/sample
new file mode 100644
index 0000000..78a1e91
--- /dev/null
+++ b/day8/sample
@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............