Press the "R" key anytime you would like to clear the screen and redraw the grid. Gridlines are spaced at 20-unit intervals. The Challenge: Create a reflection design. Use the script that I have provided, which reflects a yellow square into all 4 quadrants, as an example.
I originally created programs like these back in the 80's and 90's using Logo, LogoWriter, and MicroWorlds. It is very exciting that their decendent, Scratch, is free and online! Thanks to everyone who worked to create all these wonderful programming languages that make computer programming accessible to kids.