pxt-calliope/docs/projects/turtle-square.md
Peli de Halleux 2b504d863d
Radiodocsupdate (#1430)
* a few updates

* more updates

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* fixing hot or ocold

* more doc fixes

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* fixing docs issues

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* restore docs errors

* missing packate

* renamed argument of callback

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2018-10-15 15:32:09 -07:00

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# Turtle Square
## Introduction @unplugged
Imagine that a virtual turtle, as big as an LED, that you can control it with commands.
In this tutorial, you will learn to use the turtle and draw a square.
## Moving the turtle @fullscreen
The turtle starts in the center of the screen facing up. Place a ``||turtle:forward||`` block to make it move up.
```blocks
turtle.forward(1)
```
## Turning and moving @fullscreen
Place a ``||turtle:turnRight||`` to turn the turtle and place another ``||turtle:forward||`` block to make it move again.
```blocks
turtle.forward(1)
turtle.turnRight()
turtle.forward(1)
```
## Drawing a square
If you add enough ``||turtle:turnRight||`` and ``||turtle:forward||`` block, the turtle
will eventually draw a square.
You can move the blocks in a ``||input:on button pressed||`` to easily run the code again.
```blocks
input.onButtonPressed(Button.A, function() {
turtle.forward(1)
turtle.turnRight()
turtle.forward(1)
turtle.turnRight()
turtle.forward(1)
turtle.turnRight()
turtle.forward(1)
turtle.turnRight()
})
```
## "For" is for repetition
Have you notice the repetition pattern in the blocks needed to draw a square?
Try to use a ``for`` loop to achieve the same effect.
```blocks
input.onButtonPressed(Button.A, function() {
for(let i = 0; i <=4; ++i) {
turtle.forward(1)
turtle.turnRight()
}
})
```
## Leaving a trail
The turtle holds a pen that turns on LEDs. If you add the ``||turtle:pen||`` block,
it will leave a trail as it moves.
```blocks
input.onButtonPressed(Button.A, function() {
turtle.pen(TurtlePenMode.Down)
for(let i = 0; i <=4; ++i) {
turtle.forward(1)
turtle.turnRight()
}
})
```
```package
microturtle=github:Microsoft/pxt-microturtle#v0.0.9
```