LogicalSolver (German "LogikLöser") is a web app that helps you solving logic grid puzzles. Puzzles of this kind regularly appear for example in the German magazine P.M.-Magazin, and recently in more and more newspapers and magazines.
Of course, you can object that the puzzles are meant to train your brain, and not to be solved by a computer program. But sometimes you just cannot solve the puzzle. In this case, you can try with the app and find the mistake. And when you want to prepare such a puzzle yourself, you can check it easily and fast for consistency and completeness.
If you are still not convinced of this app's usefulness... you do not have to use it ;-) Also, you can switch off the automatic support completely, so you can try yourself and switch on the support only when you are stuck. Or just use the app as a virtual notebook, avoiding to waste paper.
UsageGenerally: If you have made an unintentional change, go "back" in your browser to undo it. Everything will be reverted to the former state.
Firstly, you have to configure the item names, the preset ones are just an example. For that, you may have to adjust the number of categories and the number of items per category. Click + and - respectively to correct the numbers. Then, enter the items into the corresponding text fields. The best way is to click " Items" first. To jump to the next field, press the tab key, or use the mouse pointer. The first category of items to enter is the one that appears only on the x axis in the triangular view.
Using another drop-down menu, you can configure the automatic logic support.
- Draw conclusions makes the app draw all logical conclusions immediately, contradictory inputs are rejected.
- Prevent contradictions draws the conclusions only in the background, but warns you when entering a contradictory relation.
- Association table does not draw any conclusions, but supports you a bit by showing (potentially wrongly) associated items in a table.
- No support switches off the logics support, and renders the app to be just a notepad.
You can reconfigure the support at any time, even after you have entered relations. If you increase the level of support, contradicting relations might be dropped partially.
You can also choose the shape of the grid view, by clicking or . The classical shape is triangular. The squared view is more symmetric, users interested in the underlying theory can spot graphical patterns. The app also utilizes the latter shape internally. On the other hand, it uses more screen space.
The squares to be marked with minus or plus are probably well-known to you. Further downwards, there is a initially empty table, which will be step-by-step filled with associated items.
Now you should enter the hints of the puzzle into the matrix by setting a plus or a minus sign in the corresponding squares. To set a minus sign, click the left mouse button. To set a plus sign, click the right mouse button or click the left mouse button while pressing down the Ctrl key, or just keep it pressed for a bit longer (for touch usage).
You cannot enter relative hints like "the Mrs X.'s street number is larger by 2 than Mr. Y' street number" directly. You have to rely on your own conclusions in this case. Alone entering such hints would be far too difficult to make it worthwhile.
In this way, you should enter one hint after the other: There might be still large gaps, but with the last hint, everything should fill up.
If you have switched on the automatic solver, all logically implied conclusions from the set squares are drawn automatically. The signs that you have entered yourself are shown in red. The other ones (black) are those which are concluded by the program. If you have made a mistake you can remove these signs again, but only those that you have entered. Just click another time in the same way. All conclusions drawn from that statement are taken back. If you want to enter a hint whose statement is already inferred, you can still enter it anyway. The sign will turn red and will be treated not only as a conclusion, but as a hint.
Saving and Sharing
The current state of the logical — including the entered items and relations — is represented by
the web address (the link), which therefore changes dynamically.
Copy the content of the address bar somewhere (e. g. a text document, or a Word document) to save the state.
To return to a saved state, copy the link back into the browser's address bar.
You can also create bookmark to the same end.
To share the riddle, send the link by mail or by messenger, share it on Facebook,
or publish it on a website or a forum page.
This approach is a bit unusual, but very convenient, as it does not need any database, account with password etc. In addition, the content is not transferred to the web server, but stays local in the browser for your privacy (technical explanation: the content is encoded behind the # symbol).