Plan Before You Type

💡 The idea

Plan a big drawing on paper first, then build it one tested part at a time.

• Sketch the picture on paper and label every part.
• Write down where each part sits, as a goto position, before you code.
• Build one part, run it, fix it. Only then start the next part.
• Comments help: a line starting with # is a note for humans, not the turtle.
• If the finished picture is wrong, you already know which block to look at.

📘 Words to know

plan

decide what to build before you build it

comment

a note in the code that the computer ignores

scene

a picture made of several parts

👀 Watch this

Only one part of the scene so far: the sun, tested on its own in the top corner.

# part one of the scene: the sun
to sun
colour yellow
fill on
circle 35
end
penup
goto -140 110
pendown
sun

▶ Run it below

✍️ Your turn

1. Run it. One part working is better than four parts half working.
2. Move the sun by changing the goto numbers.
3. Add a comment of your own with # at the start of the line.
4. Write a second block called cloud and test it by itself.
5. Only when both work, call them one after the other.

🎯 Challenge: Plan a garden: write one block for the ground and one for a flower, test each on its own, then run them together.

to ground
right 90
forward 220
back 440
end
to flower
repeat 6 [ forward 25 dot 20 back 25 right 60 ]
end
ground
goto 0 0
flower