Casa bike locks are old and tricky. So far, though, every one I've tried has a trick to getting it open, quickly and reliably. Even if you've already read this, feel free to ask me or someone else who's read this or been shown these tricks - sometimes a personal demonstration helps, too. Enjoy:
There are two common tricky points that make casa locks confusing...
1) sometimes twisting the key doesn't actually "unlock" the lock (the key doesn't do anything unless you twist it in just the right way), and
