In praise of chorded input
Speaking about LSDJ, the premiere music software for the Game Boy, George Buckenham writes:
But it also got me thinking about chorded input schemes. LSDJ is a workhorse of a program, able to do a lot of stuff. And it's designed to let you do that stuff quickly - to let you iterate fast, put down a tune fast, adjust things while you're standing on stage. But also" a Gameboy has 8 buttons - 4 directions, A, B, SELECT and START. So it has to make those buttons work hard. And that's where chording comes in.
Chording is a means of inputting commands to software by holding down multiple buttons at once. Ctrl-C is an example of a chorded command. Hold down Ctrl, then press C while you're doing it. Text copied. But you can also make chording work harder than that.
It requires a lot of planning and thinking to make a complex application controllable by only a few buttons, such as the mere 8 buttons on the original Game Boy. I wouldn't want to be in the shoes of developers who have to make things work with limitations such as these.