PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a Shading mode and a composite Yajilin mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

This is a “Franken-Friday” puzzle variation.

Theme: Mostly logical; after solving, did you notice the message in the top few rows?

Rules: Standard Cross the Streams rules. Also, the shaded region must be able to be split into tetrominoes to form a valid LITS solution.

Answer String: Enter the length in cells of each of the black segments from top to bottom for the marked columns, going in order from A to B to C to D and separating each entry with a comma.

Time Standards (highlight to view): Grandmaster = 4:00, Master = 7:30, Expert = 15:00

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools in linex mode where left click+drag draws lines and right click marks X’s)

This is a bonus “Twisted Tuesday” puzzle variation.

Theme: None?

Rules: Standard Double Back rules (originally from MellowMelon). In short: draw a single loop that enters and exits every cell exactly once, and enters and exits every region exactly twice.

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:30, Expert = 7:00

Solution: PDF

As promised, here was the original Thermo-Skyscrapers created for the USPC. I like the visual pattern and tightness of solving path much more, but it was simply too hard to use, particularly before the practice you now have from the one you saw on the USPC from yesterday’s post.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: No given numbers, and full clue cell symmetry

Rules: Standard Skyscrapers rules. Also, as in Thermo-Sudoku, digits must be strictly increasing in all thermometer shapes from round bulb to flat end.

Answer String: Enter the seven digits inside the grid for the 7th row from left to right, followed by a comma, and then the seven digits inside the grid for the 4th column from top to bottom.

Solution: PDF

The hardest puzzle I wrote for the USPC was originally intended to be presented as a subtle “surprise”. The rules would have covered what thermometer shapes do (strictly increase from bulb to flat end), but would not have been explicit that those shapes could reach outside the grid. So finding a grid with no external numbers but with many external shapes would have been a manageable but perhaps unexpected surprise. But it was decided to just be explicit here, and with some other authors in the last few months having used the same external clue ideas with skyscrapers (including myself here with an Even/Odd Skyscrapers after I knew the fate of this puzzle) it’s not clear if this would have been unexpected anyway.

I thought this was an interesting extension of some inequality skyscraper concepts I’ve seen elsewhere. My first attempt at this puzzle type was judged very elegant and far too hard. My second attempt kept one of these two traits and made it onto the test. Like the TomTom, this variation seemed to get pretty good reviews, but I do know some solvers who fell into the trap of thinking an outside number blocked that number from appearing inside the grid.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: No given numbers, and full clue cell symmetry

Rules: Standard Skyscrapers rules. Also, as in Thermo-Sudoku, digits must be strictly increasing in all thermometer shapes from round bulb to flat end.

Answer String: For the USPC, the answer string was the internal cells in the 4th row and 7th row. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

While I still want to find a good name for this variation of TomTom (Tight Fit TomTom matches the genesis story well but is probably not the best name for longevity), it was a style idea that strongly encouraged me to write for the USPC this year as it seemed a great place to debut it.

The idea actually came from Craig Kasper during a discussion of puzzle styles and possible variations. Craig didn’t think he could do it justice, but he offered it to me and I knew instantly it was a great concept to save for the future — with the USPC as the obvious first destination if it could work. I wrote two Tom/Tom puzzles (also probably not the best name — maybe in the comments people can recommend others?). The first was an easy one (10 pointer?) that became the example. The second was a tougher puzzle that has been called undervalued for 20 points by most people commenting on it. Perhaps the break-ins were not as easy to find?

The biggest struggle with the style was how to format it well; you’ll find that both of these puzzles use slashes in cells that would not normally contain the clue digit to leave more space in the fractional cells for writing numbers. Palmer’s pre-USPC example uses shaded cells and this might be a more productive route going forward. I have plans to make a bunch of TomTom variety books/puzzle packs focused on different math concepts and will probably make one around this variation when I get some larger tasks off my plate. Removing some of the extra trickiness of these samples and having simpler fractional values and even fractional clue targets should make this a good extension of TomTom puzzles for education purposes. I can even turn single cell cages into non-trivial entries!

I hope you enjoyed this variation as much as I enjoyed making it work.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between “big” sudoku and “small” number entry modes.)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between “big” sudoku and “small” number entry modes.)

Theme: Cage geometries, and the logic of the solve and new fraction rules primarily

Rules: Variation of standard TomTom rules. The indicated ranges are larger than N x N (1-6 and 1-8 respectively), and some cells containing slashes require two digits to be placed. These cells should be treated as fractional values (top value over bottom value) for the purposes of solving the puzzle.

Answer String: For the USPC, the answer string was the 5th row and 5th column of the larger puzzle. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution 1: PDF
Solution 2: PDF

I had not intended to have a repeat author for a Sunday Surprise so soon, but Craig Kasper sent along a really nice surprise sudoku to mark the US National Championship we’ve been focusing our attention on all weekend. See if you can find your way through to the very end.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: That US national championship happening this weekend; speaking of which, congratulations to the top finishers at the US Puzzle Championship, whomever you turn out to be.

Rules: Standard Sudoku rules. Also, the regions are irregularly shaped; instead of numbers, use the letters in “I’D GOLF, MAN” once in each row, column, and region.

Answer String: Enter the letters in the third column, from top to bottom, followed by the letters in the seventh column, from top to bottom. USE CAPITAL LETTERS.

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

This is a “Twisted Tuesday” puzzle variation.

Theme: None

Rules: Variation of Star Battle. There are still two stars per row and column, but instead of regions there is an irregular grid. Stars cannot be placed in adjacent cells that share an edge or corner.

Answer String: For each row from top to bottom, enter the number of the first column from the left where a star appears (gray numbers at the top of the puzzle here are given to help). Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:30, Expert = 5:00

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

This is a “Franken-Friday” puzzle variation.

Theme: No givens (this variation was inspired in part by the Even/Odd round at the 19th WPC by Lukasz Bozykowski.)

Rules: Standard Skyscrapers rules. All even digits (and only even digits) have been shaded gray. Note: this means that all unshaded digits, including unshaded outside digits, are odd.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 3rd row from left to right.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 4:00, Expert = 8:00

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

This is a “Twisted Tuesday” puzzle variation.

Theme: Hidden Clues

Rules: Standard Cave rules. Also, no number may directly connect to/”see” another number within horizontally or vertically connected cells.

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:00, Expert = 6:00

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

This is a “Franken-Friday” puzzle variation.

Theme: Hex Pill

Rules: Standard Slitherlink rules.

Answer String: Enter the length in cells of each of the internal loop segments following the arrows for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:30, Expert = 15:00

Solution: PDF