It behoves every man who values liberty of conscience for himself, to resist invasions of it in the case of others; or their case may, by change of circumstances, become his own.

It is difficult to string a tennis racket properly.

[…] Harry went into the potato patch and grabbled us some sweet potatoes […]

We reduce an instance of 3-SAT to an instance of bird-flock-optimization, using a gadget that converts each conjunctive Boolean clause to a group of birds.