The fastest way to get quick at these
Binary puzzles reward pattern recognition more than any other genre here, because the same shapes recur constantly. A pair, a gap, a line one cell from balance - there are only a handful of local situations, and getting fast is mostly a matter of seeing them without looking.
Which means volume genuinely works here, in a way it does not for every puzzle. Twenty easy boards will do more for your speed than three expert ones, because the twenty put the same shapes in front of you sixty times.
What changes as the tier goes up
Easy and medium boards fall to pairs, gaps and counting. Hard boards stall those out and require you to reason about a whole line at once: which completions are legal, and what all of them agree on. Expert boards add the assume-and-refute step on top.
The grid grows a little as well, but that is not really where the difficulty is. A large board full of pairs is easy and long. A small board that needs whole-line reasoning is short and hard, and it is graded on the reasoning.
No repeats and no waiting
Your device tracks the boards it has already given you, so a long run does not start circling. Switch tier at any point; it simply draws from elsewhere in the pool, and the no-repeat memory carries across.
Boards appear instantly because they were finished and verified before you got here. There is nothing being worked out while you wait.
Kept away from your streak
These solves feed a separate record - solved counts and average times per tier - and cannot move your Daily streak up or down. Abandon as many as you like.
That is on purpose. A streak is only worth keeping if it is a small, fixed, achievable thing. Practice should sit next to it without ever threatening it.
Common questions
How do I get faster at these?
Volume at a tier slightly below your ceiling. The same local shapes recur constantly - a pair, a gap, a line one cell from balance - and speed comes from recognising them without looking rather than from tackling harder boards.
What actually changes between the difficulties?
How deep a chain you need before anything is forced. Easy and medium fall to pairs, gaps and counting; hard requires reasoning about a whole line at once; expert adds assume-and-refute.
Are the boards different from the daily ones?
Yes, entirely separate boards, checked to the same standard. No board appears in more than one mode.