Mathcross Extra Credit Puzzles
(and More Mathcross Extra Credit Puzzles)
Puzzles marked with a star (*) are worth 5 points each. Limit is 10 points per student per quarter.
If you work with another student, you may split the points.

Puzzle
#

Choose
desired version


Description or title


Date


Rev.

22a

interactive

printable

Calculus crossword, 6 themed answers

11/7/06

6/24/07

27

interactive

printable

Old Town Alexandria

12/9/06

 

31

interactive

printable

Calculus crossword, 5 themed answers

2/20/07

 

32

interactive

printable

IntroCal

2/20/07

 

34a

interactive

printable

HappyCal

5/29/07

7/16/07

35a

interactive

printable

Space theme, suitable for everyone

6/10/07

7/2/07

37a

interactive

printable

“Couch Potatoes”

6/30/07

7/16/07

38

interactive

printable

“Math Fun” (Algebra II and above)

7/22/07

 

39

interactive

printable

“This Theme Is Self-Referential” (suitable for everyone)

8/1/07

 

41

interactive

printable

Introductory statistics, 6 themed answers

8/27/07

 

42

interactive

printable

Geometry

9/15/07

 

43

interactive

printable

Chaos and fractals

11/1/07

 

44

interactive

printable

Mystery theme

3/22/08

 

45

interactive

printable

Chaos and fractals II

6/8/08

 

46

interactive

printable

Instruments

4/5/08

 

47

interactive

printable

Precalculus

4/6/08

 

48

interactive

printable

Geometry II

6/15/08

 

49

interactive

printable

Tribute to Tim Russert, 1950-2008

6/19/08

 

50

interactive

printable

Political Symmetries

10/4/09

 

51**

interactive

printable

Big Problems Everywhere

12/23/09

 

52

interactive

printable

HappyCal II

4/17/010

 

53

interactive

printable

Almost Impossible (suitable for everyone)

6/20/010

 

54

interactive

printable

Vaguely mathematical theme

10/5/011

 

55

interactive

printable

More MODD

11/4/011

 

59

interactive

printable

Geometry IV

12/22/011

 

 

 

 

More Mathcross Puzzles (lower quality, older)

 

 

   *           Eligible for up to 5 points of extra credit (see rules at top of page).
   **        Double extra credit, up to 10 points. Rationale for the extra value for these puzzles:
                -- Puzzle #38 is “daily crossword size” (15 by 15 squares) but is super-difficult. Only 3 students have solved this puzzle so far.
                -- Puzzle #51 is extra-large, 27 by 27 squares. However, it has virtually no math and is easy except in one region, where not all of the squares are filled by letters. Only one student has solved this puzzle so far.
                -- Puzzle #53 is “Sunday crossword size” (21 by 21). The theme refers not to the puzzle, which is only medium-hard, but to activities that are almost impossible.

Notes concerning crossword standards

All puzzles listed above conform to the design standards for American crossword puzzles. Although I have not found an authoritative, canonical list, the following seem to be fairly well established as rules for publication-quality crosswords:

·         Grid pattern must be symmetric. Rotational symmetry (180°) is typical, though bilateral symmetry is also allowed.

·         Solid blocks, not bars, must separate answers.

·         No more than about 1/6 of the grid may be blocked.

·         Answers must interlock throughout the puzzle, leaving no isolated regions.

·         Each answer must be at least 3 letters long. Multiple words are allowed, and the clues nowadays seldom indicate when an answer has more than one word.

·         Each letter must be clued twice, once in an “across” clue and once in a “down” clue.

·         Tense, number, degree of formality, and abbreviation status should agree between clue and answer. For example, a colloquial answer should have a colloquial clue, and an abbreviated answer should have an abbreviated clue or the “(abbr.)” indication.

·         No inside jokes.

·         No repeated answers or stems. For example, if SPILL is an answer somewhere in the puzzle, then SPILL, SPILLS, or SPILLED cannot be answers elsewhere in the same puzzle, even if used as part of a phrase (e.g., SPILLTHEBEANS). Even short words (OF, AND, TO) should not be used in more than one answer unless required by the puzzle’s theme.

·         “Across” answers should read from left to right, and “down” answers should read from top to bottom, although rare exceptions are permitted. See, for example, the excellent puzzles in the pamphlet accompanying the DVD of the 2006 movie Wordplay.

·         No excessively tortured answers. Although clues can be tortured, especially if marked by “?” to indicate a pun or wordplay, answers should not be. All answers should be words, phrases, or portions of phrases from general knowledge, unless the answers are altered in some clever way to satisfy the puzzle’s theme. Consequently, nonsense words are usually not permitted, nor are foreign words unless they have been assimilated into English (e.g., PROTEGE) or are common knowledge (e.g., CASA). Random mash-ups (e.g., “Western bovine” as a clue for UTAHCOW) are not permitted, since they are an obvious attempt to sidestep the rule prohibiting bars as separators.

·         To the extent possible, a clue should not duplicate any portion of the answer. For example, “Animal that enjoys ants” would be a poor clue for ANTEATER.

·         Answers consisting of abbreviations, commercial trademarks, prefixes, suffixes, Roman numerals, or obscure “crosswordese” such as ADIT and DELE should be kept to a minimum.

·         If the puzzle has a theme, then the longest answers in the puzzle must conform to the theme. This rule is sometimes stated as “no non-themed answers can be longer than any themed answers,” but I find that rule overly restrictive and do not always follow it.

Since Mathcross puzzles are written for high school math and science students, I permit some entries that would be unacceptable for a general audience (for example, I would accept “5.436 . . .” as a valid clue for an answer of TWOE since 2e is approximately equal to 5.436). However, if the puzzle contains anything more cryptic or tortured than that, I would treat it as a failed puzzle. You can see some of my older, less successful puzzles on the More Mathcross Puzzles page. Many of those still qualify for extra credit!

Other requirements

There can be other requirements, such as limits on the number of clues, aesthetic standards for avoiding large clusters of black squares, and so on, but the ones listed above are the main ones. Puzzle construction is challenging, even with software to help, and many of my puzzles are not good enough to list here on the main page (see More Mathcross Puzzles for the rest).

Surprisingly, one of the most difficult requirements is the one about avoiding repeated answers. Often I will get to the end of building a puzzle, only to realize that I have to go back and rework a large portion because an answer has been used twice. The pool of 3- and 4-letter words that work well in crosswords is simply too small. For a number of years, before the budget cuts of 2008, The Washington Post would run two puzzles on Tuesdays, Wednesdays, and Thursdays, and there was almost always a word in common, even though the two puzzles came from different syndicates and different authors. Answers such as AAR, ALOE, AVOW, ERIE, ERNE, ERSE, OHIO, and TSAR are definitely overused in crossword puzzles, but if you try constructing a puzzle yourself, you will see why.


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Last updated: 05 Jun 2012