{ xTurtle Tutorial Example #1: Basics.
  
  This file demos some of the built-in
  commands of the xTurtle language.
  
  First lesson:  This is a comment,
  since it is enclosed between { and }.
  Comments are ignored by the computer.  
}
  
forward(5)  { Move turtle forward 5 units,
              drawing a line as it goes. }

turn(90)  { Rotate turtle 90 degrees,
            counterclockwise. }
            
green  { Change drawing color to green.
         Color names include red, green,
         blue, cyan, magenta, yellow,
         black, gray. }
         
forward(2)  { Move forward 2. }
back(4)     { Move backwards 4. }

{ The net result of the preceding commands
  is to draw a red and green T-shape.
  Red is the default drawing color.
}

PenUp  { When pen is up, turtle doesn't
         draw anything as it moves. }
         
MoveTo(-5,3)  { Move directly to the point
                with coordinates (-5,3) }
  
PenDown { Start drawing again. }

rgb(1,0.5,0.5) { Changes drawing color to
                 the color with red, green,
                 blue components given by
                 1, 0.5, 0.5.  This will
                 be sort-of-pink. }

face(0)  { Set turtle's heading to 0 degrees,
           meaning face to the right. }
           
circle(3)   { Draw a circle of radius 3. 
              The circle is drawn to the
              left of the turtle's current
              position. }
              
PenUp
MoveTo(-3,-7)  { Move again. }
PenDown

Magenta { Change drawing color to magenta. }

Arc(2,90)  { Draw a 90-degree arc of a
             radius-2 circle. }
forward(3) 
Arc(2,90)
forward(3)
Arc(2,90)
forward(3)
Arc(2,90)  
forward(3) { A box with rounded corners has
             been drawn. }
             
PenUp
MoveTo(5,-5)  { Move again. }
PenDown

black  { Draw in black. }
DrawText("Hello")  { Write the message Hello
                     at current cursor position. }

DrawText("World!")  { This lines up under
                      the Hello. }