# Martin Levins▸ U2: Algorithms & Programming

Use https://scratch.mit.edu/projects/10015916/ pong for remix (created by the scratch team. It’s basic, but that’s its attraction. You can experiment by changing one thing, predicting its outcome, then checking your thoughts.

Has movement control, repeat loops, decisions, randomisation

Get them to right click and “add comment” to define what each bit does. This gives a sense of accomplishment but also encourages intrinsic documentation which becomes super necessary in more complex programs or where you want to share a piece of code

Then, change the ball to another thing, add cheesy music, change the input from house to left/right arrow keys or more “traditional” game input, add a second player, add scores, but one at a time (and these are in increasing order of complexity so you may be able to offer them accordingly to the various proficiencies that will emerge)

Kids learn from one another – look for (and encourage) “elegant” ways of achieving a specific thing.

I used this to begin the ideas of interfacing with the outside world using Picoboards, but you could also use other things (see Hardware that can connect to Scratch at https://wiki.scratch.mit.edu/wiki/Hardware_That_Can_Connect_to_Scratch, or How to connect to the physical world at https://wiki.scratch.mit.edu/wiki/How_to_Connect_to_the_Physical_World

Instead of the mouse or arrow keys being used, we used a slider (variable resistor) that gave a number between 0 and 100.

Great Maths in converting the 0-100 to -200–+200 so the paddle behaved properly (and, BTW, call it “signal conditioning” to prepare them for a life in Astronomy or Biophysics or AgTech or anything that uses sensors to talk to computers.)

Can you do the Maths? (answer next week!)