SETHEADING turns the turtle to the degree position specified by its input. Positive numbers turn the turtle clockwise.
SETHEADING turns the turtle according to the direction of the screen and not the current heading of the turtle. SETHEADING 0 always heads the turtle straight up despite whatever direction it pointing.
To output the turtle's heading, use HEADING.
IF HEADING < 130 THEN NAUTILUS
This procedure slowly moves the turtle around, drawing longer lines as the heading increases.