Part I:
The small triangle you see on the screen is called "The turtle" You can use the computer's mouse to control the turtle or you can type directly commands on the command line to give the turtle instructions.
The first part of this unit introduces
the commands FD BK RT and LT.
FD means Forward and causes the
Turtle to move the specified steps in the direction it is heading.
Similarly BK means Backward. While the turtle moves it usually
draws a line. To cause it to move without drawing a line the word
"GO" is inserted before the command (GOFD and GOBK). The
command RT means Right (or Right Turn) and it causes the heading
(direction) of the turtle to turn to the right. Thus for example the
commands
FD 20 LT 45 FD 20
BK 20 RT 90 FD 20
makes a
shape that looks like the letter Y
Load
first set:
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Part II: The present unit
introduce the command MT and JT. The command moves the pointer
to the coordinate x=50 and y=40 and draws a line. The command moves
to the coordinate x=100 y=40 but does not draw a line. In the next
set of exercises use the commands JT and MT to turn to red lines in
to black
Load
second set
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Part
III: This last set of exercises uses the commands MV and GOMV.
For example MV 20 10 moves the pointer to a point 20 pixels to
the right and 10 pixels upwards from its current location, drawing a
line. GOMV is similar but does not leave a trace. Use the MV and GOMV
commands to turn the red lines into black.
Load
third set: