Pixie Scheme III implements the "R5" version of the Scheme programming language for the Apple iPad. It contains all required R5 features except a file-system interface (since the iPad does not support one), plus many enhancements. Pixie Scheme III is based on the Pixie Scheme / Wraith Scheme family of Macintosh Scheme implementations, which has been available as shareware for over 20 years. Source code for Pixie Scheme III is available under the GNU General Public License. Scheme is widely used to teach programming, and for artificial intelligence programming.