Y6 How do I use repeat, setxy and procedures in LOGO?

Start a new project with the following and save it as “y6logo 2”

• reset
• setpensize 5

Repeat task

1. repeat 4 [fd 40 rt 90] draws a square:
   1. the instructions inside the [] “fd 40 rt 90” are the ones to do again and again
   2. the “4” means repeat it four times
2. Copy the code above to draw a square
3. Copy and paste the code again
4. Try changing the 4 to a 5.  What happens?
5. Now change the “rt 90” to “rt 72”
6. Copy the code again
7. Try changing repeat to 6 – what should the “rt” number be?
8. Now try repeat 7: when you draw the shape, the total angle turned is 360 because it comes back to the beginning.  It has 7 equal angles so each angle needs to be….360…7
9. Copy the code again
10. Draw an Octagon (8-sided) and a Nonagon (9-sided)
11. Save (if you haven’t already!)

Finished?  You should have on your page:

1. A square, pentagon, hexagon, heptagon, octagon and nonagon

Setxy

1. Setxy is used to move the arrow to a different position on the canvas
2. setxy 50 100 sends the arrow to the coordinates (50, 100)
3. This Scratch project shows you what the different coordinates are:
   1. x y coordinate finder (only goes up to 240/180 in Scratch – in LOGO it goes up to 250 on each axis)
4. NOTE if the pen is down, it will draw a line to the new position – so it is quite useful to use with pu and pd:
   1. pu setxy 50 100 pd – will send it to the new place without drawing then is ready to draw
5. Use “pu setxy …. pd” to move your shapes from the first section to different places on the canvas.

Procedures

1. Procedures are used to avoid typing the same thing several times.
2. Use a procedure if you need to repeat something in your picture, eg windows in a house, snowflakes, stars, a fence, stripes, eyes….
3. A procedure teaches the computer how to do a shape but doesn’t draw it.  Then you “call” the procedure to make it draw it.
4. Instead of “repeat 4 [fd 40 rt 90]” at the beginning of your code, have this:

to square
repeat 4 [fd 40 rt 90]
end

5. When you play, it will not draw the square – you have only told it how to – not to actually draw it.
6. Now type “square”  after the procedure and it should draw the square.  You have taught it how to draw a square!
7. Procedure are usually all at the beginning of the code.
8. Make procedures called “pentagon” and “hexagon”
9. Instead of drawing one pentagon, use the code:  repeat 6 [pentagon rt 60] to make a pentagon flower!
10. Make a procedure to fill your shape:
    1. to fillshape
       1. pu rt 45 fd 10
       2. fill
       3. bk 10 lt 45 pd
    2. end
11. Call the procedure after each shape you do.

Variables

Lists

 

Success steps

• Save (as) different versions
• Experiment with new code
• Find your own mistakes by reading your code carefully
• Use repeat, setxy and procedures in your own code