ZigZag is Ted Nelson's trademark on a data model he has designed for computer interaction, both for users and between programs. The design is centered around an information structure called a zzstructure and its interactive visualizations. Nelson's stated goal is on one hand a platform for the Project Xanadu hypertext and on the other a complete computing system built on new conventions. Instead of the conventional textual formats and tree structures, zzstructure is a multidimensional extension of a spreadsheet whose cells can contain various kinds of data.