Create 40 coloured rectangles, use a for-loop, the critical thinking sheet, and do some code refactoring.
Think about your program before you code. This post goes through the five steps of the Critical Thinking Sheet.
This post starts you off with Processing. Download, run and draw some coloured lines. The computer programming language Processing, is a great way to start coding. You get a quick visual result from a few lines of code.
Values of Red, Green and Blue colours are used to code colours on a computer. Learn how to create different colours from RGB values.