In music notation a note is represented by a circle (the "note-head") drawn on a staff, either on the staff line or nestled between two staff lines depending on its pitch. The circle is drawn either filled in or not, with an attached stem or not, and with an attached flag or not, depending on the duration of the note.
A whole note is represented by an open circle. A half note adds a stem to the circle. A quarter note fills in the circle and retains the stem. An eighth note adds a flag to the stem of a quarter note. A sixteenth note adds a second flag, and additional flags are added in turn for a thirty-second note and sixty-fourth note. They look something like this:
/\
---| /-----------------------------------------------------
|/
---/-------------------------------------------------------
/| O O * * * * *
-/-|/\------------|------|------|------|-----/|-----/|-----
| | | | | | /| \| \|
|--|--|-----------|------|-----/|-----\|-----\|-----\|-----
\ | | | | \| \| \| \|
--\|_/----------------------------------------------\|-----
|
\|
When two or more eigth, sixteenth, or shorter notes occur in series, they are usually connected by beams instead of being drawn individually. The number of beams is equal to the number of flags the note would have otherwise. The following represents two eighth notes, four eighth notes, four sixteenth notes, and one eighth plus two sixteenth notes:
/\
---| /-----------------------------------------------------
|/
---/----------------*----------*----------*----------------
/| * * *| * *| * *| *
-/-|/\-----|-|---|-|-|--*---|-|-|--*---|-|-|--*------------
| | | | | | | | | | | | | | | | |
|--|--|----|-|---| | |-|----|/|\| |----| |\| |-------------
\ | | |_| |/ \| | |/ \|\| |/ \|\|
--\|_/----------------\|---------\|---------\|-------------
|
\|
In addition, a dot may follow the note-head to indicate it lasts one and a half times the duration of the note. For instance, a half note followed by a dot lasts for three beats rather than two; a quarter note followed by a dot lasts for one and a half beats rather than one. Two dots means the note lasts one and three-quarter times the duration of the undotted note.
/\
---| /-----------------------------------------------------
|/
---/-------------------------------------------------------
/| O. O. *. *. *.
-/-|/\------------|------|------|------|-------------------
| | | | | | /|
|--|--|-----------|------|-----/|-----\|-------------------
\ | | | | \| \|
--\|_/-----------------------------------------------------
|
\|
Finally, it is possible to divide a note unevenly into groups of three instead of two or four or eight, using triplet and duplet notation.
For stylistic purposes, a note may also be extended for an indefinite length of time by using a fermata.