Intro to Programming : Drawing a House

What is this 

To help everyone along in getting started with drawing the Minecraft Creeper, I asked my son to put together a program that draws a house. It uses a lot of similar elements to the Creeper that the students need to draw, and might show a few new things that we didn't cover in class yet.

The Code

   
  clear()
  println("setAnimationDelay() sets how fast the turtle speed is, invisible makes the turtle invisible but the line is still there")
  println("penUp() make the line disapear but the turtle doesn't, setFillColor(Color(0, 0 ,0)) and setPencolor(Color(0, 0, 0,))  changes the color")
  println("repeat(){ } makes the program repeat as many time as you want")
  setAnimationDelay(100)
  invisible()
  penUp()
  left()
  forward(150)
  setFillColor(Color(255, 0, 51))
  setPenColor(Color(255, 0, 51))
  penDown()
  right()
  //makes the square for the house, note the usage of 'repeat'
  repeat(4){
    forward(150)
    right()
  }
  forward(150)
  //this makes the roof
  setFillColor(Color(51, 51, 0))
  setPenColor(Color(51, 51, 0))
  right(60)
  forward(90)
  right(60)
  forward(90)
  penUp()
  //this makes the windows
  setFillColor(Color(51, 153, 255))
  setPenColor(Color(51, 153, 255))
  right(60)
  forward(40)
  right()
  forward(20)
  penDown()
  forward(30)
  right()
  forward(30)
  right()
  forward(30)
  right()
  right()
  penUp()
  forward(80)
  penDown()
  forward(30)
  left()
  forward(30)
  left()
  forward(30)
  left()
  forward(30)
  left()
  penUp()
  left()
  forward(80)
  penDown()
  //this makes the door
  setPenColor(Color(153, 68, 0))
  setFillColor(Color(153, 68, 0))
  forward(60)
  left()
  forward(35)
  left()
  forward(60)
  left()

The Outcome

The finished product looks something like this 

Intro to Programming : The First Class

.. And so it begins... 

This spring, I am teaching an "Intro to Programming" class at the After School Enrichment program at Craig Elementary, so this blog will get some new content with the progress of the class.

The First Class

In the first class, we covered quite a lot of ground : we learned quite a bit about each other, what the students in the class were interested in. As expected, most kids do enjoy video games, like learning how things work, and just plain enjoy working with computers. We briefly chatted about why people program in the first place : to express themselves, to tackle new challenges, and to be able to harness the power of computers for their own inventions.

We covered some of the basic concepts of what a program is : a sequence of instructions that follow some specific grammar rules (just like they do in English). We had a quick introduction to Kojo (our programming environment, more on that later) and the various elements of Kojo's user interface - the command / script area, the drawing area, the menus, the output / error message area. Most importantly, we focused on how to continue learning from the environment - using code completion / prompts to see the syntax of commands that we hadn't used before, reading the command documentation. We also spent some time learning to recover from failure, when something unexpected happens - resetting the zoom level on the drawing area (if one accidentally zoomed out too far), and just bringing up the right windows if one of them suddenly disappeared.

Our first programming exercise really didn't involve a computer : I asked my students to "program me" and command me from one side of the room to the other, while avoiding the obstacles along the way - chairs, large metal poles, backpacks. I did attempt to behave like a computer - I just followed the instructions that were given to me and failed a few times along the way - ran into an office chair, gonked my head against the metal pole. In order to tie up with what came next (which was drawing a square in our programming environment), I then asked the kids to use the same commands that they used to guide me through the room, but this time, to make me walk in a square along the tiled floor using the same limited set of commands - e.g. left, right, forward, back.


So, with the basic commands under our belt, the kids got to programming. We learned how to draw a square. First everyone came up with a short program for a square, and then we experimented with variations on the topic - some of the kids really enjoyed drawing BIG squares and seeing the turtle in action while it was drawing the squares. Then, for the more ambitious students, we tried drawing a triangle (and yes, this is where the geometry skills came shining through - what were the angles in an equilateral triangle, you ask :-) ). The example looks something like this :

The takeaway : for the kids who want a little challenge at home, I asked them to practice drawing a Minecraft Creeper, which very roughly, looks like this - it will give the kids a chance to practice some of the skills that they've already picked up (e.g. drawing squares), but also give a chance to learn a few new things as well (using background and fill colors)

Setting up Kojo

Kojo is a very kid-friendly piece of software which was created specifically to help children learn about programming and have fun along the way. It should run on all modern OS-s (Windows, Linux, MacOS), so as long as you have a desktop computer to install this on (but it will not work on a tablet), your child should be able to continue exploring it on their own. It contains a rich library of examples written in Kojo (which we will lean on in the class) - it even has a game or two that the kids can play with.

Setting up Kojo is pretty straighforward:
1. Dowload Kojo from http://www.kogics.net/kojo-download
2. Run the downloaded .jar file (e.g. by right clicking and choosing "Run" on windows), it will launch the installer - just follow through the installer and you should have an icon on your desktop that you can use to launch the software.