Good news: somerby.net/mack/logic now has a cancel button. If a decision is taking too long, you can cancel it and continue working. You don't have to close the browser anymore.
Bad news: somerby.net/mack/logic is not working in Internet Explorer, or at least it isn't working in Internet Explorer 11 on my computer. I'll try to fix it soon.
It works for me in Chrome and Firefox. I'd appreciate it if anyone tells me whether or not its working for them in other browsers. Just leave a comment on this post.