part A

The item that I like to use is my mp3 player.
It is small, thin, curvy, and easy to use.

visibility:
-big display screen
-full colour, bright and clear
-current status and choices are clearly visible
-diplays every necessary information such as
artist, album, song title, length, time, volume, equilizer, etc

feedback:
-visible feedback is very bright and clear.
-It makes little 'beep' sound everytime user presses a button.


affordance:
-easy to learn the control
-easy to predict what is going to happen after
pressing the buttons because there is arrows and +, - signs

mapping:
-location of the control buttons are gathered on the front,
which is convenient to press even for the left-handed users.
-graphics on the display and associated buttons are near each other

constraints:
-hold button keeps the mp3 locked
-earplug and usb is located far from each other, so it prevents
users to actually look for the right place to plug something
-there is a cap where users plug in the usb, so it can prevent
itself from getting damaged

habituation:
-there are only few buttons so the users can memorize the control easily