This is a gem of a puzzle from A Moscow Math Circle, Week by Week Problem Sets by Sergey Dorichenko.
Can a 10×10 square be paved with 1×4 rectangular stone plates?
As always, please send your answers as comments within the blog (preferred), or send an e-mail to alokgoyal_2001@yahoo.com. Please do share the puzzle with others if you like, and please also send puzzles that you have come across that you think I can share in this blog.
Happy paving!