They are written by the Grabarchuk family, who is one of the most original and productive puzzle creators in the world. Hailing from the western Ukrainian city of Uzhgorod on the border with Slovakia, the family moved to the United States in 2013 as it became internationally known for its puzzle books, websites and applications. Computer science legend Donald Knuth says that Serhiy Grabarchuk, the father of the tribe, “has my vote as the current jigsaw puzzle winner in the world. His works are very beautiful, instructive and satisfying “. Since the beginning of the war, the Grabarchuks have been publishing a daily puzzle that promotes Ukrainian culture (as it “marked the difference” in Hagia Sophia at the top of this story) in hopes of raising money for humanitarian and military aid. Below are six puzzles I selected from the family archive. If you like them, consider contributing to their suggested causes. Slava of Ukraine!

  1. Hex vex Which digit should replace the question mark?
  2. Ring Which ring system is different from the others?
  3. Snake shake Which view of the 11 cube snake is wrong?
  4. Box fox Put a digit in each box so that all 8 equations, lengthwise and downwards, are all correct. A box already has a digit. This puzzle was created in collaboration with Harry Nelson
  5. Sign mine Which of the marks in the bottom row should replace the question mark?
  6. Elementary For each of these six elements, find another element that has nothing in common with the corresponding letter. Each answer is unique. Created in collaboration with Donald Knuth Hint: all answers are known facts, words found in the vocabulary of a non-chemical. NO SPOILERS. I will be back at 5 p.m. United Kingdom with answers. UPDATE: Read the solutions here. Grabarchuk’s story began five decades ago when Serhiy, now 64, was a student in Uzhgorod. He discovered a talent for making puzzles and magic tricks and turned it into a career. By the 1990s, he and his wife Tanya had a small company that published puzzle books, and now the business has expanded to include websites and applications, including his sons, Serhiy Jr. and Peter, and their wives, Kate and Helen. The most successful family puzzle is Strimko, a puzzle in pencil and paper in the style of Sudoku. The Grabarchuk family Photo: The Grabarchuk family If you liked today’s puzzles, consider donating to Ukraine. Following are links to donation pages of the National Bank of Ukraine for humanitarian and military support. Grabarchuks are on Facebook, Instagram and here is their website. Their most recent books are the Age of Puzzles series. All images in this story are copyrighted. I put a puzzle here every two weeks on Monday. I’m always on the lookout for great puzzles. If you want to suggest one, email me. I am the author of many puzzle books, most recently Language Lover’s Puzzle Book. I also give school talks on math and puzzles (online and in person). If your school is interested, please contact us. On Thursday, April 21 I will do a puzzle workshop for the Masterclasses Guardian. You can register here.