Reddit reviews The Puzzling Adventures of Dr. Ecco (Dover Recreational Math)
We found 2 Reddit comments about The Puzzling Adventures of Dr. Ecco (Dover Recreational Math). Here are the top ones, ranked by their Reddit score.
I'm taking that as well. Haven't found anything on pdf or kindle though. I believe we are using The Puzzling Adventures of Dr. Ecco.
To piggyback on this, if OP is studying an introduction to discrete math course, this book has some really useful example problems, including this odd door problem.