Line the participants up in two lines facing each other. Give the participants 30 seconds to look at  each  other  closely,  paying  close  attention  to  small  details.  The  first  row  of  participants  turns and faces the opposite direction while the participants in the other line change something about themselves.  For  example  someone  might  take  off  their  tie,  or  put  their  hair  down.  When  the participants  turn  around,  they  have  to  guess  how  the  person  they  observed  has  changed themselves. The participants then switch places.