callum's planck layout

This is a layout for the grid planck, built with a few ideals in mind:

Consistent and minimal response times should be maintained. Keys that react differently depending on whether they are tapped or held, keys that react differently if they are double tapped, etc. should be avoided – they inevitably send their keycode later than a normal key – interrupting the immediate feedback from the screen. Therefore we restrict ourselves to chording as our only means of getting more than one symbol out of a single physical key.
The hands should never need to leave the home position. The usual culprit for this is the arrow cluster, so the arrow cluster should be as close to home as possible.
There should be two of every modifier (one on each side), otherwise certain long key combinations become hard to make.
It should be possible to do things you might want to do while using the mouse with only the left hand (e.g. change tabs, navigate back or forwards in browser history).
Symbols should be arranged so that the most frequently used are easiest to reach. This includes numbers, and lower numbers are more commonly used than higher ones. (number arrangement borrowed from dustypomeleau's minidox layout.