Selecting a puzzle: Click the table, type the serial number like 342-20587 and press ENTER.

Each of these puzzles is solved by two or more swaps of numbers in the table.

The target is to make the computed sums (yellow background) equal to the correct sums (white background) by suitable swaps.

Click the the first of the numbers to be swapped and this cell will be painted green and then the second one and this cell is painted red. The numbers are thus swapped.

To start the same game again, click the small blue square in the right bottom corner.

To start a new game, click the small red square.

Clicking of the yellow small square in the right upper corner opens various options. You may change the size of the puzzle (from 2x3 to 6x8) and the degree of difficulty by selecting the maximum number of swaps needed etc. Clicking the yellow square again removes the display of these options.

Further extensions: Survo puzzles combined with picture puzzles.

If your web browser does not support this Java applet, use a Javascript version.

Finding a correct solution is not always easy especially when more than two swaps are needed. You may get training in this game by letting the program show the swaps needed. This takes place by clicking the playing area very close to the left upper corner. A new such a click removes these hints. Another alternative is to click the playing area very close to the left lower corner. Then the incorrectly located numbers are displayed on another background color. These hints are not available for games with an even serial number shown in the in the right bottom corner. It is of the form mns-N where mn indicates the size mxn, s the maximum number of swaps needed, and N is an integer.

Games (N in their serial numbers) are selected at random. However, you may select an earlier game simply by typing its serial number and ENTER.

Use of the keyboard enables still more possibilities. For example, by the serial number -554-222111 a 5x5 problem with 4 swaps is obtained. '-' in front of the serial number removes the row and column sums from the display.

Survo puzzles of form 2xn, 3xn, 4xn, 5xn, and 6xn for n=3,4,5,6,7,8 are available. The number of swaps may vary from two to nine.

Since the trailing part can be any of the integers from 1 to 999999 and there are 30 combinations of row and column dimensions, the number of Survo puzzles available on this page is tens of millions.

In each puzzle on this page, the numbers are originally located in places according to the products of row and columns sums. This setup is typically close to the correct solution which can be achieved by a few swaps (i.e. interchanges of numbers). More information about the swapping method

At the moment, only a few (10) pictorial puzzles are available. One of them is selected randomly by clicking a small green square. Any of them can be selected by typing its index (#1 - #10) and pressing ENTER.

The display may be modified by clicking small buttons
P,N,G located above the table.

P removes or restores the pictures.

N removes or restores the numbers.

G draws grid lines separating the cells or removes these lines.

More information about Survo puzzles

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