It is always fun to share some favourite puzzles and talk about recreational mathematics. Down below I share a selection of puzzles I use in math festivals, plus some notes, sources and ideas. They are mainly watercolor on wood. Some are classics, some are originals, most lie somewhere in between. 

Sources and Resources

These are some sources I use for ideas of puzzles.  

Wikipedia page for classics- Here one can find details on many of the cult puzzles. Ones from the list that I include in my festival repertuar are the 8 queens puzzle (a favorite), the knight's tour, and the three utilities puzzle (which is a bit unfair as there is no solution). I also try to include Soma's cube, pentomino tilings and the T-puzzle as more hands-on manipulation puzzles, but keep losing pieces.

Martin Gardner- Long time authour of the Mathematical Games column in the Scientific American magazine, he has tons of books and works on puzzles. Here is a dedicated website.

Henry Ernest Dudeney - He has great puzzle books, including 536 Puzzles and Curious Problems that hooked me up on puzzles a life time ago, when I picked it up from my high school library. Some of his work is in public domain now, and can be found on Project Gutenberg here.

Printible Puzzles - There are quite a few website that provide free printable puzzles for educational use, both in and outside the classroom.  The roosters and fence puzzles are inspired by Father Brown's brain benders from  puzzles-to-print.com.  I am also planning to try a math crossword from the same site for festival use.