It's easy to make the usual form of a sad face smiley.
The sad face smiley is simply a reversal of the familiar smiley smile.
Lighted smiley faces are sometimes used at the roadside to indicate whether you are driving below or above the speed limit. Very effective. Facial expressions are understood instantly. You can see at a glance if Big Brother is smiling or frowning.
You know the accepted wisdom of the smiley world. An internet smiley can be any colour as long as it's yellow.
I hate to disillusion you, but a sad face smiley to use when you are blue is more effective if it's - well, blue.
Smileys, super or sober, 3d, animated or plain, are always always round.
...Except when they are another shape to make life more exciting. If you're having a go at making your own sad face emoticon, you could try a tear drop for a glum expression.
Smileys show they are unhappy with an upside-down smile.
Hey! Wait a minute. Try that in the mirror. Pull down the corners of your mouth as far as they can go. You may get a comical 'Oooh-Er!' grimace. You might even look like a smiley. But do you really look sad?
Hmmm. You may feel a bit on the saggy side when you are feeling despondent, but in fact the middle of your lower lip goes up when you are really sad. You only look ' down in the mouth'.
Escalate to a full scale crying fit and your upper lip stretches sideways. Your whole face scrunches up towards the middle as if to squeeze out the tears. Only the outer parts of the brows go down.
As a matter of fact, I cannot think of any occasion when you would want to use a really sad face smiley or emoticon. Emoticons so often mean "only joking"...
Sad faces of the more realistic kind can work better for other symbols like theatre masks
TIP: To add instant despondency to a sad face smiley, simply give an upward twitch to the inner ends of the eyebrows.