Logo
Programming
Worksheet for Wednesday, October 9th
1. ROUTINES
A routine is a series of Logo commands,
usually used to create a geometric
drawing.
For
example, REPEAT 4[FD 50 RT 90] is a logo routine that draws a square with each side 50 units long. (Read and try the routines on pages 842-845
and do problems #3-5 on page 852.)
2. PROCEDURES
Defining a procedure:
A procedure
is a series of Logo commands that have been given a specific name so that the computer can store the commands
and use them later whenever you use the name of the procedure. It allows you to create your own dictionary
of terms in the Logo program’s short-term memory. For example,
TO
SQUARE
REPEAT 4[FD 50 RT 90]
END
To
indicate that you want to create a procedure you begin with the word TO followed by the name of your
procedure. To indicate you are finished
with your instructions you use the word END. When you define a procedure, no picture is
drawn, it just stores the instructions under the name you gave them.
Using a procedure:
To use your procedure to draw a picture you just type its name. For example, type SQUARE and the computer
follows the instructions stored under that name and draws a square.
(Read
the middle of page 845 and do problems #6-8 on page 852.)
Variables in a procedure:
You
can use a variable in a procedure. This allows you to use the same set of
instructions but use different numbers in place of the variable. For example, edit your square procedure by
typing EDIT SQUARE. Then type in the :N
in the title of your procedure and in place of the 50.
To
exit the editor screen use the F2 key at the top of your keyboard. Do not click on the X in the upper
right of the screen since this closes the editor window without saving the
changes you made.
TO
SQUARE :N
REPEAT 4[FD :N RT 90]
END
When
you use the procedure you type its name followed by the number you want to
use for the variable. For
example, SQUARE 50 will draw a square with each side 50 units long.
(Note: When using the procedure you do not
type the word TO and you do not type a colon in front of the number
50.) SQUARE 20 will draw a square with
each side 20 units long.
**
See page 847 for a procedure that defines a parallelogram with variables for the
size of
the
angles and sides. Study the examples of
the parallelograms created by using the name of the procedure with different
numbers for the angle and sides. Type
into your computer the parallelogram procedure as shown on page 847 and then
use it to do # 9 page 852.
Next
reread page 845, then do page 853 # L12.1 & L12.2.
Using Logo to illustrate symmetry
Worksheet
for Friday, October 18th.
Class will be held in BR 161.
Create
a procedure to make a flag.
REPEAT
4 [FD 50 RT 90]
BK
60
END
Type
in the word FLAG to have the computer draw a flag.
Use
this procedure to illustrate rotational symmetry.
Type
these routines to experiment with different rotational symmetries.
Keep
a record of your results and comment about the rotational symmetry of each.
REPEAT
3 [FLAG RT 120]
Type
CS to clear the screen and then type:
REPEAT
5 [FLAG RT 72]
Type
CS to clear the screen and then type:
REPEAT
6 [FLAG RT 60]
Type
CS to clear the screen and then type:
REPEAT
10 [FLAG RT 36]
Use
a square to illustrate lines of symmetry.
REPEAT
4[FD :N RT 90]
END
Type
in these instructions:
SQUARE
10
SQUARE
20
SQUARE
30
SQUARE
40
Do
you see a diagonal line of symmetry?
Look
for rotational symmetry and lines of symmetry in each figure. Write down the smallest degrees of
rotational symmetry and the number of lines of symmetry and that you see in
each figure.
Type
in these instructions:
REPEAT
4[SQUARE 50 RT 360/4]
Type
CS to clear the screen and then type:
REPEAT
8[SQUARE 50 RT 360/ 8]
Type
CS to clear the screen and then type:
REPEAT
12[SQUARE 50 RT 360/ 12
Type
CS to clear the screen and then type:
REPEAT
24[SQUARE 50 RT 360/24]
(You
can test your ideas about the symmetry by having the turtle draw appropriate
lines through the figures.)