The World's 200 Hardest Brain Teasers: Mind-Boggling Puzzles, Problems, and Curious Questions to Sharpen Your Brain - PDF
نویسندگان: Gary Gruber
خلاصه: From acclaimed author Dr. Gary Gruber, whose proven critical-thinking methods have sold more than seven million books, this collection of mind-bending brain teasers is sure to challenge even the most experienced problem solver. Inside are logic puzzles, riddles, maddening math problems, mental games, and more!