Melbourne University Mathematics and Statistics Society

 Solution for 3.1 Mouths (Answer = LAUGHTER)

The first thing to notice here is the slightly unusual grouping of the pictures. Since each group is between 1 and 5 pictures long, using Morse code seems like a good idea. Assigning a dot to an open mouth and a dash to a closed one spells out the message "2NDLETTER." The only thing left to do now is to identify the owners of the mouths. Coincidentally, they all turn out to comedians, and we can identify them as in the table:

 Comedian Shape of mouth Morse code 2nd Letter DWAYNE JOHNSON o ..--- (2) W CHARLIE CHAPLIN o H DAVE CHAPPELLE – A STEVE MARTIN – T TIM MINCHIN – I ASHTON KUTCHER – -. (N) S STEPHEN COLBERT o T CHEVY CHASE – -.. (D) H JERRY SEINFELD o E ABBOTT AND COSTELLO o B MEL BROOKS o .-.. (L) E ESTELLE GETTY – S STEVE CARELL o T AMY SCHUMER o M DENISE SCOTT o . (E) E EDDIE MURPHY – - (T) D JIM CARREY – - (T) I SCOTT THOMPSON o . (E) C BILL BAILEY o .-. (R) I ANDY LEE – N NEIL PATRICK HARRIS o E

Taking the second letters of their names spells out WHAT IS THE BEST MEDICINE, a clue for the answer LAUGHTER.

Author's Notes:
This puzzle was inspired by one of those stupid games people play at high school summer camps. The game is called open and closed and goes something like this.

The smug person at the table who already knows how the game works initiates it by making a shape on the table with their hands and announcing whether or not it is 'open' or 'closed'. They do a few of these, much to the bewilderment of the others at the table who can't seem to work out what makes something open or closed. Alas, it's all a diversion! Whether or not something is open or closed has nothing to do with what the person's hands are doing, but instead whether or not their mouth remains open or closed at the end of their announcement. As people catch on, the size of the smug group grows, slowly isolating those who are left in the dust. Cruel, I know, but such is the puzzling life.

I must apologise for the low quality image of Denise Scott. For some reason I missed all the high quality images of her online. Nonetheless, it was never intended for any team to correctly identify all the comedians, just enough to make out the clue.