Write on Windows, Edit on Linux, View on Mac. Or any other order. Rainbow Board works and looks the same everywhere. Save the whole whiteboard as a ".rainbow" file and open the same file on any OS.
Create and switch between multiple pages in a single whiteboard. Save all the pages along with undo-redo information as a ".rainbow" file or save individual pages as images.
The whiteboard responds to stylus as well has hand touches. Draw perfect handwriting.