Web Paint-by-Number Forum
Topic #178: Check & Reveal & Hint
By Daniele (daniele)

#1: Daniele (daniele) on Jul 3, 2009

I'm new to webpbn, so I hope I'm not breaking any etiquette with this post. In any case, I'm already addicted, and think the site is fabulous, though I had an idea and wonder what others think:

I think it'd be helpful to have a 'check' button on the playing page which would mark the incorrectly filled-in boxes (to be used at the player's discretion). B/c while the red dot is obviously helpful, just undoing from there isn't necessarily sufficient, since as far as I understand, you could've made a mistake earlier but it was still 'logical' so you don't know how much to undo. So this way, you'd know which ones to undo and then could pick up and move forward from there.

I can also envision a 'reveal' button, where if someone is really stuck, they can reveal one tile, and then hopefully pick up from there. I've seen both of these options on the kenken.com site, and I've used both in a pinch.

Alternatively, or in addition, there could be a 'hint' button where you can see if any of your markings are wrong and undo them, and if all's good, it can show you a box that you could logically fill in.

Happy 4th!
#2: Jan Wolter (jan) on Jul 3, 2009
I'm kind of inclined to think that something of this flavor would be a good idea.

I think they are a degree "cheatier" than the red dots, because they actually give you information that can't be seen from looking at the puzzle. But if you are 3/4 of the way through a 50x60 puzzle, and you hit a contradiction where either way you mark a cell gives you a red dot, and you have no idea how long ago you made the error, it's harsh to either have to abandon the puzzle or start over from ground zero. Same thing if you just get completely stuck and can't find another cell to mark. It'd be nice for there to be something that can help you along a bit so you can get on with solving the rest of the puzzle. Yeah, you could peek at the solution, but that kind of spoils the fun of the puzzle. So I think "cheaty" helpers could be nice for getting you out of such messes, and would let people get the maximum enjoyment out of the puzzle, if they choose to use them.

One thing I think might be nice would be to have an option to automatically undo to the point where you first marked a cell incorrectly. That's not too hard to implement.

Something that would give you a hint, in the form of one cell you can mark would be a bit harder, if you want it to mark a cell for you that actually makes logical sense.

I hope to have some programming time for webpbn sometime soon. Maybe I'll do something along these lines. But I'm interested in how other users would feel about such features.
#3: Adam Nielson (monkeyboy) on Jul 4, 2009
Hi Daniele; welcome. Good points you brought up.

Jan, I think this feature that you mentioned would be the best:

"One thing I think might be nice would be to have an option to automatically undo to the point where you first marked a cell incorrectly."

If it shows you which one was wrong, and you can revert to that point, it would save a load of frustration.

If you were to implement the one-cell "reveal" feature, though, how would you do it? How would it know which cell to show? Any random one? Would this be able to be used time and time again throughout a puzzle?

This feature would definitely be nice on a lot of the puzzles that require guessing, because instead of guessing, I usually peek at a part of the the solution (hiding most of it and just peeking at one corner so I don't spoil the whole image). But seeing just one correct pixel might be very nice.
#4: Teresa K (fasstar) on Jul 4, 2009
Jan, the option to go back to just before one makes the first mistake would be so helpful. It would be nice to have a button like that for real life. I have a few mistakes I'd like to undo. :-)
#5: Teresa K (fasstar) on Jul 4, 2009
#6: Adam Nielson (monkeyboy) on Jul 4, 2009
Oops, lol

You do? :-)
#7: Byrdie (byrdie) on Jul 4, 2009
I also agree with the above, having had to clear a couple puzzles and start over (ok, maybe more than a couple) because i got quite a ways down line from a mistake I made.

I have a puzzle game on my other computer that takes any image you select, breaks it into squares for the grid size you chose and then rearranges them for you to put back into order. It has a help cheat that marks all the squares that are out of position with a red cross hatch. You can't do any rearranging while that's turned on but it does give you the ability to see what needs to be moved to complete the puzzle.

Just my 2 cents.
#8: Jan Wolter (jan) on Jul 5, 2009
With a "reveal a cell" function, I'd ideally like it to reveal a cell that is actually logically reachable from the current state. Maybe it would even say something about why that cell is settable. That is much harder to do than just having it set a random cell, but I think it would be much more useful. I could probably do that using pbnsolve, but pbnsolve runs server side, and using it that way could cost a lot of server load (which costs me money). So I don't know if I could make that work.

The "undo to first error" option would certainly doable, and it sounds like it would be popular.
#9: Daniele (daniele) on Jul 7, 2009
Adam - thanks for the welcome:) Just one question - what is the 'peek'? I couldn't find that anywhere.

Yay, my first contribution and it's popular:)
#10: Adam Nielson (monkeyboy) on Jul 7, 2009
There is no "peek" option. What I was referring to was when I need to look at the solution of a puzzle, just to see a pixel or two when I get stuck, I open the solution but cover it with my hand or a paper or something. Then I slowly move whatever I am covering the solution with in order to see one tiny corner of the puzzle. That way I don't spoil the whole image, and I am able to "peek" at a small portion.
#11: Daniele (daniele) on Aug 5, 2009
Ooops, been a while, but how do you see a solution to a puzzle if you haven't solved it?
#12: Robyn Broyles (ginkgo100) on Aug 5, 2009
Hover your mouse over the puzzle link on the list. Don't click on the link, just hover. You'll get a pop-up window with the option to "peek at solution."
#13: Daniele (daniele) on Aug 5, 2009
What 'list' are you referring to? I don't see anything that just says 'puzzle'.
#14: Jan Wolter (jan) on Aug 7, 2009
This list of puzzles on the "Home" or "Find Puzzles" pages. There is also a peek link on the discussion page for the puzzle. There isn't a peek link on the puzzle solving page for the puzzle itself.
#15: Daniele (daniele) on Aug 10, 2009
Aha! Ok, I found it in the 'home' and 'find puzzles' pages. I don't see it on the 'view and make comments' page (is that what you mean by 'discussion' page?). Also, up till now, I've been using 'random puzzle', and it doesn't seem to be an option there.
#16: Spot (Pspaughtamus) on Apr 10, 2018
I have issue with the Check feature. I use it for the larger, more complex puzzles, and those with too much white space. I'm finding that I can click on it and get "solution ok so far..." for several separate trials, then I may be close to 3/4 done, click check, get told there's an error, I'll click to undo to first error, expecting only a few squares, and it might clear out almost all of my completed work. Is that a glitch?
#17: Norma Dee (norm0908) on Apr 10, 2018
I have had that happen several times. I think I am OK because it's telling me so, so I blindly click thinking it's a recent error only to have it wipe out most of the completed work. So I learned the hard way to save, save, save. :)

Since Jan is no longer with us, I doubt that this problem will be fixed.
#18: Spot (Pspaughtamus) on Apr 10, 2018
Thanks, Norma, I'd about decided that was what I'd have to do.

I'm still fairly new to this site but I'm going through the old puzzles so I'm familiar with many of the long-timers. What happened to Jan, and when?
#19: Norma Dee (norm0908) on Apr 10, 2018
He passed away unexpectedly on January 2, 2015 from complications of the flu. He gave us a great gift of this site and we are very lucky that his companion, Valerie has decided to keep it going in his memory.
#20: Kristen Vognild (kristen) on Apr 11, 2018
I think that what it does with the "first error" is to check from row to row, then column to column. If the error is near the top of the puzzle, that wipes out everything below the error. I *try* to remember to save often (and in a complex search-and-click puzzle, I save after each new pixel. Place, then Check, then Save).
#21: Wombat (wombatilim) on Apr 11, 2018
I always save immediately after a successful check as well... the undo to first error command has yet to bring me to a point prior to my most recent save, but I like to have the known good save just to be sure.

I'm also usually doing the puzzles while I'm waiting for other things to happen on my computer, so the frequent saves are important in case I need to quit my browser for one reason or another.
#22: Joe (infrapinklizzard) on Jul 1, 2020
It is very possible to make a mistake and then move to another section and make a whole bunch of correct moves. The Check would then go through your undo list until that mistake is undone, erasing all the correct stuff that you had done afterward.
#23: LoloJean (LoloJean) on Feb 29, 2024
Depending on how much the error impacted your later work, you can can undo to the first error, redo the error square, manually clear the incorrect square, then keep using the redo button to bring back other work you'd done. The redo button will still work even if you've edited squares since undoing.
#24: Joe (infrapinklizzard) on Mar 6, 2024
Note that you have to do it exactly as LoloJean says. That is because of a quirk of the Undo algorithm: it only stores the final color of the square you're in. If you change anything other than the square that the error is in, the Undo list is truncated and the new move is added on.
#25: Valerie Mates (valerie) on Mar 8, 2024
I just found this thread. Fixing "undo to first error" is on my To Do list. I know which place in the code needs fixing, and I do intend to dive into it someday.

Instead of using "Undo to first error," I do something similar to what LoloJean does: I undo over and over again, about ten at a time, until "Check" says the puzzle is okay, using Undo and Redo and Check until I find what the error was. Then I click Redo over and over again, until all my work is back again. Then I fix the error and click Check to see if the puzzle is correct again. Sometimes it isn't, but often it is.
#26: gregg licht (Lgreg) on Jun 14, 2024
Valerie, I do almost the same thing, but I fix the error as soon as I've gone back far enough to find it. Then you can still Redo and occasionally Check on your way back...your fix is not undone. Sometimes there are later errors related to your original error, and I can sometimes fix those while Redo-ing back to the most recent puzzle state.
#27: Valerie Mates (valerie) on Jun 14, 2024
I did not know that Redo would work after I made a new change. Interesting!

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