ballistic calculator block.
insert target location (xyz) + current location (xyz) and it spits out the elevation (2 numbers, low+high arc) + angle (relative to north) to manually aim at.
maybe/opotionally could be synced to a radar to give fireing solution for entity targets (speed not taken into account if that would be too hard)
makes arty fire easier for those who can't do computer craft stuff. and prevents the need for external stuff