To install the appstore app, right-click on your turtle to open the GUI, run
pastebin get iXRkjNsG appstore. To install buildcheckerboard, run
appstore get AlSweigart buildcheckerboard.
Builds a checkeboard floor out of coal and quartz blocks.
This program is used in Chapter 13 of Coding with Minecraft. You can view it at https://turtleappstore.com/book/chapter13.html