[Splines]

I think it's interesting that "correcthorsebatterystapl" is more secure than "correcthorsebatterystaple".

Makes sense, but it's amusing to see the time drop as you add letters.

[nosignal]

I noticed this too. It seems advice to "pick random words" should be extended to "pick random words and leave the last letter off".

[mokus]

That only doubles the size of the attacker's dictionary, though. Instead, I'd say "pick random words and add a few random typos". As long as there aren't too many the typos will be as memorable as the words themselves (more so if you're a spelling pedant like me), and using a variety of typos instead of just one simple transformation increases the search space a lot more.