In psychology, the STROOP effect is a demonstration of interference in the reaction time of a task. 

When the name of a color (blue, green, red) is printed in a color which is not denoted by the name (the word "red" printed in blue ink instead of red ink), naming the color of the word takes longer and is more prone to errors than when the color of the ink matches the name of the color. 

In the principle of STROOP, this set of props can be developed into many routines and combined into a complete set of performances. 

1. Super Responsiveness: The magician tries to challenge the limits of humans and flawlessly identifies the color of the word on any page that the spectator looks at. 

2. Super Memory: The spectator can open a page freely, and the magician can recite the color of all the words on this page in order. 

3. Super Insight: The spectator opens to any page; the magician knows this page number by the spectator's micro-expressions. 

4. Mind Reading: The magician guesses the color that the spectator has in mind.

• No need to remember, no peeking
• Can be performed immediately, no sleights
• Clever page number design, can be used with any tricks dealing with numbers
• New choice for book testing
• Additional blank version of the book, so that the routine can be performed on the stage and interact with audiences
• Comes with velvet bag, easy to carry
• You don't need to know the page number to read the content of the page. You can also know the page number without knowing the content of the page