XO is built from free and open-source software. Our commitment to software freedom gives children the opportunity to use their laplets on their own terms. While we do not expect every child to become a programmer, we do not want any ceiling imposed on those children who choose to modify their machines. We are using open-document formats for much the same reason: transparency is empowering. The children—and their teachers—will have the freedom to reshape, reinvent, and reapply their software, hardware, and content.