Challenging Math Puzzles

Can quantum operations, recombinant shapes, and concealed distribution actually lead to fun? Sure they can! Just try these optical illusions, mechanical aptitude puzzles, maps and mazes. "Selections are interesting."

Honest Illusions by Nora Robertsby Nora Roberts

America's favorite writer" (The New Yorker) unveils a world where nothing is as it seems.  
 The daughter of a world-renowned magician, Roxy Nouvelle has inherited her father's talents-and his penchant for jewel thievery. Into this colorful world comes Luke Callahan, an escape artist who captures her heart-and keeps secrets that could shatter all her illusions...

Optical Illusion Magic: Visual Tricks & Amusements

Illustrated in full colour, these optical illusions are cool and fun for all ages. Entertain yourself or impress your friends for hours. Boggle your mind with afterimages, impossible figures, flip-flopping faces, and more that will confuse your vision. Figure out what the secret message is in letters that are stretched out. Look at two lines and decide which one is longer (or are they both the same length?). “Bend” a rigid pencil. Stare at a pattern of triangles and see how your mind organizes them into all sorts of imaginary patterns, shapes, peaks, and shades.

 

Incredible Visual Illusions (You won't believe your eyes!)

Incredible Visual Illusions is the most comprehensive and amazing collection of optical illusions ever assembled, with close to three hundred different illusions, many of which have never before been published. You will be amazed as images flash and scintillate before your eyes, other images disappear right before your eyes, other images disappear right in front of your eyes, size and shape lose their meaning, and you see motion where there is no motion.

This book is truly a visual feast for the eyes, a fun book just to browse and look at or to learn about visual illusions.
The theory about how each optical illusion works can be very simple, or very complex, sometimes requiring advanced neurophysiology and even mathematics and calculus to understand, so there's great variation in terms of the range of difficulty and complexity.
Anyway the learning experiences you can get out of visual illusions are a greater understanding - & appreciation - of how the brain really works & its innate abilities.