trivial, fruitful optimization for node placement
trivial, fruitful optimization for node placement

remember previous crossing lines/travel costs rather than re-computing
them on every iteration

pivotal-devin-fallak/atc,savaki/atc,simonjjones/atc,savaki/atc,pivotal-devin-fallak/atc,simonjjones/atc,pivotal-devin-fallak/atc,zachgersh/atc,savaki/atc,zachgersh/atc,utako/atc,utako/atc,utako/atc,zachgersh/atc,zachgersh/atc,simonjjones/atc