User`s manual

pendown (pd) put the turtle’s pen down and draws a

line when the turtle moves.(default status)

showturtle (st) make the turtle shape visible.(default

status)

hideturtle (ht) make the turtle shape invisible

home move the turtle to the center of the

screen, points the turtle straight up (HEADING 0), but does not clear

the graphics screen or alter the pen

state.

clearscreen (cs) erase the graphics screen, returns the

turtle to the center of the screen, and

sets the turtle’s heading to

0.CLEARSCREEN does not affect the pen state or screen colors.

xcor output the X coordinate of the turtle

ycor output the Y coordinate of the turtle

heading output the turtle’s degree

turtlestate (ts) output the turtle’s propery

wrap WRAP makes the turtle remain inside

the graphics window no matter how large a movement command is

given. Any time the turtle moves off the

window borders, it wraps around the window

and reappears on the opposite edge.

window WINDOW removes the boundaries from

the turtle’s field of movement. If the turtle

moves beyond the borders of the graphics

window, it continues to move, but cannot

be seen.

fence FENCE prevents the turtle from moving

beyond the edge of the graphics window.

If you try to move the turtle off the

window, it does not move and Logo displays a

message.

2. Mathematics instruction

abs output the absolute value of its input.

arctan output the arctangent of its input.

cos output the cosine of its input.

expn calculate the natural base e (2.7183. . .)

raised to the power specified by its input.

Untitled-3 10/16/01, 2:37 PM29