Technology: Logo: MicroWorlds
Topic: Geometric Shapes

Instructing Logo how to draw different geometric shapes provides students with a graphic way to understand the geometric properties of the figures and discover new ones.
Ask students to describe the geometric shape as if they were walking on the figure. This also gives students with opportunity to experience diverse ways of achieving the same effect.
It also important to ask students to tell in English how to make the figure and convert the description into Logo and vice versa.

English Logo Commands Procedures
TO make a SQUARE (sq.) of side 100,
put the PENCIL DOWN (pd),
move FORWARD (fd) 100,
turn RIGHT  (rt.) 90 degrees.
Repeat the steps there more times

pd
fd 100
rt. 90
fd 100 rt. 90
fd 100 rt. 90
fd 100 rt. 90
or more briefly
pd
repeat 4[FD 100 rt. 90]

Logo Practice Board

to sq
pd
repeat 4[FD 100 rt. 90]
end
TO make a TRIANGLE (trio), put the PENCIL DOWN (pd), turn RIGHT 30 degrees,
move FORWARD (FD) 100,
turn RIGHT 120 degrees,
move FORWARD (FD) 100,
turn RIGHT 120 degrees
move FORWARD (FD) 100.

pd
rt. 30
FD 100
rt. 120
FD 100
rt. 120
FD 100

Logo Practice Board

to tri
pd
rt 30
fd 100
repeat 2[rt 120 fd 100]
end
TO make a HOUSE (hs) of size 100,
put the PENCIL DOWN (pd),
make a SQUARE(sq) of size 100,
move the turtle (pencil) to the top of the square,
turn RIGHT (rt) 30 degrees,
make a TRIANGLE (tri) of size 100,
turn LEFT (lt),
move BACK (bk) to the bottom of the square.

pd
repeat 4[fd 100 rt 90]
fd 100
rt 30
fd 100
rt 120
fd 100
bk 100

or. if the procedures sq and tri are already defined,

pd
sq
fd 100
rt 30
tri
lt 30
bk 100

Logo Practice Board

to hs
pd
sq
fd 100
rt 30
tri
lt 30
bk 100
end

The concept of variables should be introduced right away since it arises naturally when one wants to repeat the same type of figures but with different sizes. The commands above can be easily adjusted to draw squares, triangles and houses of any size.

English Procedures
TO make a SQUARE (sq.) of any size,
put the PENCIL DOWN (pd),
move FORWARD (fd) size,
turn RIGHT  (rt.) 90 degrees.
Repeat the steps there more times
to sq :size
pd
repeat 4[FD size rt. 90]
end
TO make a TRIANGLE (tri) of any size,
put the PENCIL DOWN (pd),
turn RIGHT 30 degrees,
move FORWARD (FD) size,
turn RIGHT 120 degrees,
move FORWARD (FD) size,
turn RIGHT 120 degrees
move FORWARD (FD) size.
to tri :size
pd
rt 30
fd size
repeat 2[rt 120 fd size]
end
TO make a HOUSE (hs) of size,
put the PENCIL DOWN (pd),
make a SQUARE(sq) of size size,
move the turtle (pencil) to the top of the square,
turn RIGHT (rt) 30 degrees,
make a TRIANGLE (tri) of size size,
turn LEFT (lt),
move BACK (bk) to the bottom of the square.
to hs :size
pd
sq :size
fd size
rt 30
tri :size
lt 30
bk size
end

To procedures sq, tri and hs have all the variable "size".  The command sq 20 will draw a square of size 20, tri 30 will draw a triangle of size 30, hs 75 will create house of size 75 and son on.

Note,
1. As it should be with any variable, its name is not important, in the examples above we use "size" as a variable just to remind us what represents, but we could have used any other name of just a single letter (as long as it is not a logo command)
2. The definition of hs assumes that the procedures sq and tri had been previously defined.

Click on go to create different shapes!

 


Procedures

Logo Practice Board

Polygons A Mayan Pyramid

 

Extensions
1. Students can create and define their own shapes and find geometric properties that characterize them. They will define procedures for the new shapes. 
2. Students can be asked to write the procedures to produce given pictures
3. They can import a background and animate bees and birds to trace the shapes.


 2000-01  M. Llarull - Department of Mathematics - NJTQEC - William Paterson University