Do you have a version for the iPhone, iPad, or iPod Touch?
Not yet, but we're working on it.
If you have problems registering the software:
Visit www.PacificT.com/register for detailed instructions.
The blue grid doesn't show up when printed or on overhead projection.
You can make the grid darker by graphing sin ax * sin ay = 0. Set a so that the solutions are the grid lines. In the default zoom, use a=2π. Darker2DGridLines.gcf demonstrates.
How can I label the x-axis in units of π?
You can label the x-axis by pasting pictures next to it. AxisInUnitsOfPi.gcf uses this feature to add labels at units of π.