diff --git a/gallery/gitea.png b/gallery/gitea.png
new file mode 100644
index 0000000..7d2874c
Binary files /dev/null and b/gallery/gitea.png differ
diff --git a/gallery/notes.pdf b/gallery/notes.pdf
new file mode 100644
index 0000000..7e65f04
Binary files /dev/null and b/gallery/notes.pdf differ
diff --git a/gallery/notes.typ b/gallery/notes.typ
new file mode 100644
index 0000000..f2f20fa
--- /dev/null
+++ b/gallery/notes.typ
@@ -0,0 +1,114 @@
+#import "/src/lib.typ" as chronos: *
+
+#set page(width: auto, height: auto)
+#chronos.diagram({
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob")
+
+  _seq("a", "b", comment: [hello])
+  _note("left", [this is a first note])
+
+  _seq("b", "a", comment: [ok])
+  _note("right", [this is another note])
+
+  _seq("b", "b", comment: [I am thinking])
+  _note("left", [a note\ can also be defined\ on several lines])
+})
+
+#pagebreak()
+
+#chronos.diagram({
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob")
+
+  _note("left", [This is displayed\ left of Alice.], pos: "a", color: rgb("#00FFFF"))
+  _note("right", [This is displayed right of Alice.], pos: "a")
+  _note("over", [This is displayed over Alice.], pos: "a")
+  _note("over", [This is displayed\ over Bob and Alice.], pos: ("a", "b"), color: rgb("#FFAAAA"))
+  _note("over", [This is yet another\ example of\ a long note.], pos: ("a", "b"))
+})
+
+#pagebreak()
+
+#chronos.diagram({
+  _par("caller")
+  _par("server")
+
+  _seq("caller", "server", comment: [conReq])
+  _note("over", [idle], pos: "caller", shape: "hex")
+  _seq("server", "caller", comment: [conConf])
+  _note("over", ["r" as rectangle\ "h" as hexagon], pos: "server", shape: "rect")
+  _note("over", [this is\ on several\ lines], pos: "server", shape: "rect")
+  _note("over", [this is\ on several\ lines], pos: "caller", shape: "hex")
+})
+
+#pagebreak()
+
+#chronos.diagram({
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob")
+  _par("c", display-name: "Charlie")
+
+  _seq("a", "b", comment: [m1])
+  _seq("b", "c", comment: [m2])
+
+  _note("over", [Old method for note over all part. with:\ `note over FirstPart, LastPart`.], pos: ("a", "c"))
+  _note("across", [New method with:\ `note across`.])
+
+  _seq("b", "a")
+
+  _note("across", [Note across all part.], shape: "hex")
+})
+
+#pagebreak()
+
+#chronos.diagram({
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob")
+
+  _note("over", [initial state of Alice], pos: "a")
+  _note("over", [initial state of Bob], pos: "b")
+  _seq("b", "a", comment: [hello])
+})
+
+#chronos.diagram({
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob")
+
+  _note("over", [initial state of Alice], pos: "a")
+  _note("over", [initial state of Bob], pos: "b", aligned: true)
+  _seq("b", "a", comment: [hello])
+})
+
+#pagebreak()
+
+#chronos.diagram({
+  _par("a", display-name: [Alice])
+  _par("b", display-name: [The *Famous* Bob])
+
+  _seq("a", "b", comment: [hello #strike([there])])
+
+  _gap()
+  _seq("b", "a", comment: [ok])
+  _note("left", [
+    This is *bold*\
+    This is _italics_\
+    This is `monospaced`\
+    This is #strike([stroked])\
+    This is #underline([underlined])\
+    This is #underline([waved])\
+  ])
+
+  _seq("a", "b", comment: [A _well formatted_ message])
+  _note("right", [
+    This is #box(text([displayed], size: 18pt), fill: rgb("#5F9EA0"))\
+    #underline([left of]) Alice.
+  ], pos: "a")
+  _note("left", [
+    #underline([This], stroke: red) is #text([displayed], fill: rgb("#118888"))\
+    *#text([left of], fill: rgb("#800080")) #strike([Alice], stroke: red) Bob.*
+  ], pos: "b")
+  _note("over", [
+    #underline([This is hosted], stroke: rgb("#FF33FF")) by #box(baseline: 50%, image("gitea.png", width: 1cm, height: 1cm, fit: "contain"))
+  ], pos: ("a", "b"))
+})
\ No newline at end of file
diff --git a/src/consts.typ b/src/consts.typ
index bac5d0c..8db4541 100644
--- a/src/consts.typ
+++ b/src/consts.typ
@@ -15,6 +15,12 @@
 #let COLLECTIONS-DY = 3
 #let QUEUE-PAD = (5pt, 3pt)
 
+#let NOTE-PAD = (6, 3)
+#let NOTE-CORNER-SIZE = 6
+#let NOTE-GAP = 3
+#let NOTE-HEX-PAD = (6, 8)
+
 #let COL-DESTRUCTION = rgb("#A80238")
 #let COL-GRP-NAME = rgb("#EEEEEE")
-#let COL-SEP-NAME = rgb("#EEEEEE")
\ No newline at end of file
+#let COL-SEP-NAME = rgb("#EEEEEE")
+#let COL-NOTE = rgb("#FEFFDD")
\ No newline at end of file
diff --git a/src/diagram.typ b/src/diagram.typ
index c2c2656..48685dc 100644
--- a/src/diagram.typ
+++ b/src/diagram.typ
@@ -57,7 +57,8 @@
 
   // List participants
   let linked = ()
-  for elmt in elmts {
+  let last-seq = none
+  for (i, elmt) in elmts.enumerate() {
     if elmt.type == "par" {
       participants.push(elmt)
     } else if elmt.type == "seq" {
@@ -73,15 +74,44 @@
         participants.at(i).from-start = false
       }
 
+      let p1 = elmt.p1
+      let p2 = elmt.p2
       if elmt.p1 == "?" {
-        linked.push("?" + elmt.p2)
-      } else {
-        linked.push(elmt.p1)
+        p1 = "?" + elmt.p2
       }
       if elmt.p2 == "?" {
-        linked.push(elmt.p1 + "?")
-      } else {
-        linked.push(elmt.p2)
+        p2 = elmt.p1 + "?"
+      }
+      linked.push(p1)
+      linked.push(p2)
+      last-seq = (
+        elmt: elmt,
+        i: i,
+        p1: p1,
+        p2: p2
+      )
+    } else if elmt.type == "note" {
+      elmt.insert("linked", elmt.pos == none and elmt.side != "across")
+      if elmt.pos == none and elmt.side != "across" {
+        let names = participants.map(p => p.name)
+        let i1 = names.position(n => n == last-seq.p1)
+        let i2 = names.position(n => n == last-seq.p2)
+        let pars = ((i1, last-seq.p1), (i2, last-seq.p2)).sorted(key: p => p.first())
+        if elmt.side == "left" {
+          elmt.pos = pars.first().last()
+        } else if elmt.side == "right" {
+          elmt.pos = pars.last().last()
+        }
+
+        let seq = last-seq.elmt
+        seq.insert("linked-note", elmt)
+        elmts.at(last-seq.i) = seq
+      }
+      elmts.at(i) = elmt
+      if elmt.side == "left" {
+        linked.push("[")
+      } else if elmt.side == "right" {
+        linked.push("]")
       }
     }
   }
@@ -137,6 +167,7 @@
     }
   }
 
+  set text(font: "Source Sans 3")
   render(participants, elmts)
 }
 
diff --git a/src/lib.typ b/src/lib.typ
index 8574fbd..f44c8e9 100644
--- a/src/lib.typ
+++ b/src/lib.typ
@@ -3,4 +3,5 @@
 #import "sequence.typ": _seq
 #import "group.typ": _grp
 #import "participant.typ": _par
-#import "separator.typ": _sep
\ No newline at end of file
+#import "separator.typ": _sep
+#import "note.typ": _note
\ No newline at end of file
diff --git a/src/note.typ b/src/note.typ
new file mode 100644
index 0000000..39281da
--- /dev/null
+++ b/src/note.typ
@@ -0,0 +1,171 @@
+#import "@preview/cetz:0.2.2": draw
+#import "consts.typ": *
+
+#let SIDES = (
+  "left",
+  "right",
+  "over",
+  "across"
+)
+
+#let SHAPES = (
+  "default",
+  "rect",
+  "hex"
+)
+
+#let _note(side, content, pos: none, color: COL-NOTE, shape: "default", aligned: false) = {
+  return ((
+    type: "note",
+    side: side,
+    content: content,
+    pos: pos,
+    color: color,
+    shape: shape,
+    aligned: aligned
+  ),)
+}
+
+#let get-note-box(note) = {
+  let PAD = if note.shape == "hex" {NOTE-HEX-PAD} else {NOTE-PAD}
+  let inset = (
+    left: PAD.last() * 1pt,
+    right: PAD.last() * 1pt,
+    top: PAD.first() * 1pt,
+    bottom: PAD.first() * 1pt,
+  )
+  if note.shape == "default" {
+    inset.right += NOTE-CORNER-SIZE * 1pt
+  }
+  if note.side == "left" {
+    inset.right += NOTE-GAP * 1pt
+  } else if note.side == "right" {
+    inset.left += NOTE-GAP * 1pt
+  }
+  return box(note.content, inset: inset)
+}
+
+#let get-size(note) = {
+  let PAD = if note.shape == "hex" {NOTE-HEX-PAD} else {NOTE-PAD}
+  let m = measure(box(note.content))
+  let w = m.width / 1pt + PAD.last() * 2
+  let h = m.height / 1pt + PAD.first() * 2
+  if note.shape == "default" {
+    w += NOTE-CORNER-SIZE
+  }
+  return (
+    width: w,
+    height: h
+  )
+}
+
+#let _get-base-x(pars-i, x-pos, note) = {
+  if note.side == "across" {
+    return (x-pos.first() + x-pos.last()) / 2
+  }
+  if note.side == "over" {
+    if type(note.pos) == array {
+      let xs = note.pos.map(par => x-pos.at(pars-i.at(par)))
+      return xs.sum() / xs.len()
+    }
+  }
+  return x-pos.at(pars-i.at(note.pos))
+}
+
+#let render(pars-i, x-pos, note, y, lifelines) = {
+  let shapes = ()
+  let PAD = if note.shape == "hex" {NOTE-HEX-PAD} else {NOTE-PAD}
+  let m = measure(box(note.content))
+  let w = m.width / 1pt + PAD.last() * 2
+  let h = m.height / 1pt + PAD.first() * 2
+  let total-w = w
+  if note.shape == "default" {
+    total-w += NOTE-CORNER-SIZE
+  }
+
+  let base-x = _get-base-x(pars-i, x-pos, note)
+
+  let i = none
+  if note.pos != none and type(note.pos) == str {
+    i = pars-i.at(note.pos)
+  }
+  let x0 = base-x
+  if note.side == "left" {
+    x0 -= NOTE-GAP
+    x0 -= total-w
+    if lifelines.at(i).level != 0 {
+      x0 -= LIFELINE-W / 2
+    }
+  } else if note.side == "right" {
+    x0 += NOTE-GAP
+    x0 -= lifelines.at(i).level * LIFELINE-W / 2
+  } else if note.side == "over" or note.side == "across" {
+    x0 -= total-w / 2
+  }
+
+  let x1 = x0 + w
+  let x2 = x0 + total-w
+  let y0 = y
+
+  if note.linked {
+    y0 += h / 2
+  }
+  let y1 = y0 - h
+
+  if note.shape == "default" {
+    shapes += draw.merge-path(
+      stroke: black + .5pt,
+      fill: note.color,
+      close: true,
+      {
+        draw.line(
+          (x0, y0),
+          (x1, y0),
+          (x2, y0 - NOTE-CORNER-SIZE),
+          (x2, y1),
+          (x0, y1)
+        )
+      }
+    )
+    shapes += draw.line((x1, y0), (x1, y0 - NOTE-CORNER-SIZE), (x2, y0 - NOTE-CORNER-SIZE), stroke: black + .5pt)
+  } else if note.shape == "rect" {
+    shapes += draw.rect(
+      (x0, y0),
+      (x2, y1),
+      stroke: black + .5pt,
+      fill: note.color
+    )
+  } else if note.shape == "hex" {
+    let lx = x0 + PAD.last()
+    let rx = x2 - PAD.last()
+    let my = (y0 + y1) / 2
+    shapes += draw.merge-path(
+      stroke: black + .5pt,
+      fill: note.color,
+      close: true,
+      {
+        draw.line(
+          (lx, y0),
+          (rx, y0),
+          (x2, my),
+          (rx, y1),
+          (lx, y1),
+          (x0, my),
+        )
+      }
+    )
+  }
+
+  shapes += draw.content(
+    ((x0 + x1)/2, (y0 + y1)/2),
+    note.content,
+    anchor: "center"
+  )
+
+  if note.pos != none or note.side == "across" {
+    y -= h
+  }
+
+  let r = (y, shapes)
+  return r
+}
\ No newline at end of file
diff --git a/src/renderer.typ b/src/renderer.typ
index bd78e8b..540a4ce 100644
--- a/src/renderer.typ
+++ b/src/renderer.typ
@@ -6,6 +6,7 @@
 #import "sequence.typ"
 #import "separator.typ"
 #import "consts.typ": *
+#import "note.typ" as note: get-note-box
 
 #let DEBUG-INVISIBLE = false
 
@@ -61,6 +62,29 @@
         par.max-lifelines = calc.max(par.max-lifelines, par.lifeline-lvl)
       }
       participants.at(i) = par
+    
+    } else if elmt.type == "note" {
+      let (p1, p2) = (none, none)
+      if elmt.side == "left" {
+        p1 = "["
+        p2 = elmt.pos
+      } else if elmt.side == "right" {
+        p1 = elmt.pos
+        p2 = "]"
+      }
+
+      if p1 != none and p2 != none {
+        let i1 = pars-i.at(p1)
+        let i2 = pars-i.at(p2)
+        cells.push(
+          (
+            elmt: elmt,
+            i1: i1,
+            i2: i2,
+            cell: get-note-box(elmt)
+          )
+        )
+      }
     }
   }
 
@@ -143,6 +167,7 @@
   let draw-group = group.render.with()
   let draw-sep = separator.render.with(x-pos)
   let draw-par = participant.render.with(x-pos)
+  let draw-note = note.render.with(pars-i, x-pos)
   
   // Draw participants (start)
   for p in participants {
@@ -223,6 +248,15 @@
         line.lines.push(("create", y))
       }
       lifelines.at(i) = line
+    
+    // Note
+    } else if elmt.type == "note" {
+      if not elmt.linked {
+        y -= Y-SPACE
+        let shps
+        (y, shps) = draw-note(elmt, y, lifelines)
+        shapes += shps
+      }
     }
   }
 
diff --git a/src/sequence.typ b/src/sequence.typ
index 23dd557..cc81393 100644
--- a/src/sequence.typ
+++ b/src/sequence.typ
@@ -1,6 +1,7 @@
 #import "@preview/cetz:0.2.2": draw
 #import "consts.typ": *
 #import "participant.typ"
+#import "note.typ"
 
 #let get-arrow-marks(sym, color) = {
   if type(sym) == array {
@@ -61,10 +62,15 @@
 
   y -= Y-SPACE
 
+  let h = 0
   // Reserve space for comment
   if elmt.comment != none {
-    y -= measure(box(elmt.comment)).height / 1pt + 6
+    h = calc.max(h, measure(box(elmt.comment)).height / 1pt + 6)
   }
+  if "linked-note" in elmt {
+    h = calc.max(h, note.get-size(elmt.linked-note).height / 2)
+  }
+  y -= h
 
   let i1 = pars-i.at(elmt.p1)
   let i2 = pars-i.at(elmt.p2)
@@ -148,6 +154,12 @@
     )
   )
 
+  let y0 = y
+  if "linked-note" in elmt {
+    let shps = note.render(pars-i, x-pos, elmt.linked-note, y, lifelines).last()
+    shapes += shps
+  }
+
   if elmt.p1 == elmt.p2 {
     if elmt.flip {
       x1 = start-info.lx
@@ -210,6 +222,11 @@
     lifelines.at(i2) = dst-line
   }
 
+  if "linked-note" in elmt {
+    let m = note.get-size(elmt.linked-note)
+    y = calc.min(y, y0 - m.height / 2)
+  }
+
   let r = (y, lifelines, shapes)
   return r
 }
\ No newline at end of file