Michael is a remarkable polymath, he has the chops not to only get these applications written but also meet Apples' standards review in a single try. His jammer related applications are:
HexJam ($2)- Hexagonal Jammer Concertina for the iPhone or iPod Touch
HexJam HD ($2) - Hexagonal Jammer Concertina for the iPad
It links to an Apple or Windows PC (probably Linux too) wirelessly. There are simple instructions for hooking it up. There's no direct sound.
This is remarkable; in about five short years, we have gone from where it took Jim Plamondon, a gang of people and a largish fortune to just develop prototypes of jammers, to where it was implemented as a short project by one guy. True, he's working from the large body of background knowledge and work that's accumulated (I modestly point to these two Wikipedia articles: Jammer_keyboard and Wicki-Hayden note layout), and true, this 1.0 version does not have important musical features like velocity. But still ... it does give one pause.
Limitations: as in all version 1.0 products, there are some
little limitations. The basic one is that we didn't get too fancy;
Michael delivered what the basic apple application package could easily
deliver. This means basically, one finger at a preset velocity per note,
and fancy things like a thumb-pad area for the thumb, finger-tip
expression control (i.e. vibrato), motion sensing and and ... all sorts
of bells and whistles have been left on the workbench. Tough. Better
okay and now, than perfect and never. Yet, even at this stage these
applications go well beyond the toy.
This application is a fully-customizable multiple-layout isomorphic musical
keyboard. Each hexagon on the screen is a note, and surrounding
hexagons are harmonically related according to the rules you select. The blurb reads:
Jordan Rugress's a