Y5: LF Make procedures with variables

Recap

• What is a procedure?
• How do we code a procedure?
• How do we make a new procedure?

New skill

Procedure with variables = procedures that can draw different sizes (or colours, shapes,…)

Here’s the original c procedure:

to c
fd 20    rt 90    fd 20    bk 20    lt 90    bk 20    rt 90    fd 20    lt 90
end

Here’s an example of a c procedure with variable.  What is the difference?

to c :size
fd :size   rt 90   fd :size   bk :size   lt 90   bk :size   rt 90    fd :size   lt 90
end

Tasks

1. Open this fie c size procedure  and save it as your onw
   1. Make it draw bigger and smaller Cs in different places (use pu setxy 100 100 pd  between each c shape)
2. Add another variable  :pen that changes the pen size
   1. Add :pen to the “to” line after :size
   2. Inside the procedure add a line  setpensize :pen
   3. When you type c, you now need two numbers – how big and how thick the pen is.
   4. Add a second number to your Cs to make 5 Cs with different sizes and thicknesses
3. ** Write your own letter procedure with a variable :size instead of fd/bk numbers
4. *** Can you include a :col variable to choose the colour?

See these posts for more ideas and techniques:

• Draw letter rainbows, flowers and shapes
• Stars and shapes 2
• Stars and shapes 1
• The power of procedures with variables
• Use variables to draw spirals
• Use variables to draw shapes
• Random
• Repeat, setxy, procedures

LOGO example files – can you work out how they work?

• Letter procedures
• Rectangle four variables
• Random colour wheel
• Spiral code
• Another spiral