Sebastian sets a very simple puzzle

Here's a description of the contestant's attempt. Someone's probably working on collecting some images to illustrate it.

Sebastian sets a pretty simple set of clues to his code in four quadrants of a single piece of paper: a drawing of a tree, for '3'; nine lines, for '9'; a drawing of Australia, with text indicating that only the last letter is of interest - with 'A' corresponding to the number '1'; and then an empty quadrant, indicating a '0'. Julie solves the puzzle in just 1 minute and 23 seconds. Despite setting such an easy puzzle, Sebastian earns third place in the task.

(Written by Karl Craven)