The Lekh Diagram was initially released for iPad and now it is available for iPhone too. It is a universal app, which will run on both: iPhone and iPad.
The new release also adds support for a most wanted feature: zooming drawing canvas. This feature is available on both: iPhone and iPad
The UI of iPhone version is designed such a way that, you will get almost full of the screen as drawing area. It has a small tool bar which can be collapsed. When the toolbar is collapsed, you will get whole of the screen as drawing area except for small corner area where there is expand button.
The zooming drawing canvas feature will be very useful on iPhone. You can draw various shapes on normal zoom and then later can view whole of the diagram by zooming out. You can also do most of the re-arrangement of shapes while canvas is zoomed-out.
App store link: https://itunes.apple.com/us/app/lekh-diagram/id576124115?mt=8
Learn more about Lekh Diagram: http://www.avabodh.com/lekh
Get updates on twitter: https://twitter.com/avabodh
iPhone version demo