some sort of support for handling rounding issues nicely, eg. if the user supplies 3 equal values then the percentages shown all be "33%" which doesn't add up to 100%. I'm not sure what can be done about that though.
better space management - the current blocking system is a bit crude (low priority). This would probably require some iterative method of checking for overlaps for different graph elements rather than blocking down to a box.
shortcuts for fountain fill segments, ie. instead of having to call: