3

## Sliding Calendar Puzzle

Published on Sunday, January 01, 2012 in , , , , ,

### Rules

Somebody has mixed up the calendar! Can you help straighten it out?

Just like the 15 puzzle, the object of this puzzle is to return all the pieces to their correct order. Instead of 15 pieces to move around, however, the puzzle below has 41 pieces. In addition, the calendar aspect adds an extra dimension to the challenge!

Note the year and month above the calendar puzzle itself. Your challenge is to arrange the pieces so that they form the correct calendar for that month and year. The following rules apply:

• The blue square marked with a “1” will always be located somewhere in the top row. This should make sense. You don't start any calendar on the 2nd week.

• The blue numbered tiles are arranged on their corresponding days in the month. If the 1st fell on a Tuesday in the given month, then the blue “1” needs to be placed in the Tuesday column, and so on.

• The blue numbered tiles must be arranged in numerical order, reading from left to right, then top to bottom.

• The white lettered tiles are used to fill in the remaining spaces not used by the dates, and must be arrange in alphabetical order, reading from left to right, then top to bottom.

For example, if you're given a 30-day month that begins on Tuesday, the goal would be to arrange the puzzle like this:

Note, in this example, that A and B are used to fill the first Sunday and Monday respectively, since the month begins on a Tuesday. After the month ends, the remaining lettered pieces, C through K, are used to fill the remaining spaces.

The Year Range selection menus can be used to choose the range of years for your next puzzle (the default range is 2000 to 2099), and the New Puzzle button will generate a new month and year, as well as shuffle the pieces.

For help in solving the puzzle, try the next section.

Post your record times and moves, along with the year and month you solved, in the comments!

### Solving

The two challenges that were combined to make the sliding calendar puzzle are taught separately here in the Grey Matters Mental Gym.

First, learn how to solve the classic versions of the 15 puzzle in this tutorial.

After that, you need to learn how to determine the day of the week for any given date.

To apply them to this particular puzzle, consider the year and month you're given, along with the first of the month. Once you figure out on which day of the week the first day falls, you also know which lettered tiles (if any) come before it.

Once you get the first lettered and numbered tiles in place, it's mostly like solving the original 15 puzzle.

When you get to the last two rows, the tricky part becomes working out which letter goes below which other piece. If you take into account where the letters in the top row (again, if any) left off, and how many days are in the month, this isn't too difficult.

Yes, you could cheat and look up the given month calendar online, but it's far more impressive to do it without looking.