# I need tough riddles and puzzles **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [January 25, 2020, 1:26am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930 "2020-01-25T01:26:17Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [January 25, 2020, 1:26am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/1 "2020-01-25T01:26:17Z")
I’ve been doing prison ministry for some time now (writing letters to inmates) and many of them are intelligent brains being wasted behind bars. One wants tough, fun riddles and puzzles to solve. What are some riddles or puzzles that are genuinely tough and intellectual; so hard they’d take days? (Must be fun too, no Einstein math) ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [January 25, 2020, 1:42am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/2 "2020-01-25T01:42:16Z")
Rather than list individual puzzles, I’ll list some sources. [NPR’s Sunday Puzzles](https://www.npr.org/series/4473090/sunday-puzzle) vary in difficulty. Occasionally I can solve them within seconds. More often I never find the solution. In the middle are the ones that take an hour or two to figure out, or a couple of days of mulling them over. If you follow that link, you’ll find an archive of puzzles. There’s a button for a transcript; the challenge for the week appears near the end of the transcript. These are mostly word puzzles, lots of anagrams and puns and the like. Sample (on the very easy side): > [@](#): > > Everyone knows what a spoonerism is, right? That’s where you switch the initial consonant sounds of one phrase to get another — like “light rain” for “right lane.” Here’s the puzzle: Name a well-known world leader, first and last names. Spoonerize this, and you’ll get a phrase that means “to have confidence in one of the martial arts.” Who’s the leader, and what’s the phrase? [Car Talk Puzzlers](https://stage.cartalk.com/radio/puzzler) are similar puzzles, but are more logic puzzles or creative-solution puzzles. A lot of them were car-related, but a lot weren’t. A sample: > [@](#): > > RAY: This week’s puzzler was sent in by a fellow named Peter Brigham. Of course, I had to embellish, obfuscate and unclarify it – not to mention add the necessary folkloric and historic elements. Here it is: > > A young fellow goes into a convenience store to buy a couple of things. He buys a package of razor blades, shaving cream, a bottle of cheap aftershave lotion and a candy bar. The clerk rings up his total and it comes out to $13.59. > > The fellow opens his wallet. He’s got a buck. He says, “Oh man…oh, wait a minute. I have an emergency $50 tucked in my wallet.” He takes it out. He hands the fellow the fifty-dollar bill. The cashier gives him his change, and as he does so, the cashier says," That’s interesting!" > > The customer says, “Geez, it is!” > > So, what’s so darn interesting? > Answer: > > [spoiler]TOM: I remember my first reaction was that the change that he got was some permutation of thirteen fifty-nine, which is what he spent. > > RAY: No. It was the change. And what’s interesting is he gets a 20, a 10, a five, a one, a quarter, a dime, a nickel and a penny. There are eight little things in the cash register. He gets from each.[/spoiler] Finally, [Fivethirtyeight’s “The Riddler”](https://fivethirtyeight.com/tag/the-riddler/). These are often pretty math-heavy, and even though the math they involve is generally high-school math and below, I confess I rarely can figure them out. But there are a lot of puzzles there and may be worth checking out. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [January 25, 2020, 2:36am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/3 "2020-01-25T02:36:34Z")
Ah, great stuff, thanks! ---
**Author:** ![Unreconstructed\_Man](https://avatars.discourse-cdn.com/v4/letter/u/76d3ee/32.png) [@Unreconstructed\_Man](https://boards.straightdope.com/u/Unreconstructed_Man)\ **Post date:** [January 25, 2020, 2:44am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/4 "2020-01-25T02:44:46Z")
If you’re willing to shell out, buy a copy of the GCHQ puzzle book. You can also check out [www.pandamagazine.com](http://www.pandamagazine.com) a bimonthly magazine with an emphasis on MIT Mystery Hunt style puzzles. Both are very good quality and will keep you busy for a long time. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [January 25, 2020, 3:22am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/5 "2020-01-25T03:22:45Z")
If the person knows how to play chess, [retrograde analysis problems](https://www.janko.at/Retros/index.htm) can be very absorbing. You don’t have to play well, you just need to know the rules. They’re basically logic problems revolving around how to legally get into various bizarre chess positions. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [January 25, 2020, 4:03am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/6 "2020-01-25T04:03:25Z")
Two personal favorite puzzles. I’m not suggesting these’ll take days to solve, but the solutions are satisfying to me. First one is how I remember an old Car talk puzzler: > [@](#): > > You have seven rolls of coins, 100 coins in each roll. The problem is, you suspect some of the coins might be counterfeit. > > There’s good news. All the coins in a roll are either genuine or counterfeit; the rolls are definitely not a mix. The counterfeit coins weigh 11 grams each, whereas the real coins weigh 10 grams each. And I’m willing to let you use my digital scale which is accurate to the gram. > > But there’s bad news: you don’t know which rolls are counterfeit, or how many rolls are counterfeit, or even if any of the rolls are counterfeit. Also, I’m only willing to let you use my scale for free one time–that is, to get one single reading. After you conduct one weighing, I’m gonna charge you for each additional use. > > So, what’s the smallest number of weighings you can do to figure out which rolls if any are counterfeits? And once you realize you can do it in just a single weighing, how do you do it? And then there’s this one, which I heavily adapted from an old logic puzzle: > [@](#): > > My first job was driving the delivery truck for a bottled tea company. They made two varieties of tea: sweet and unsweet; the tea itself looks identical whether or not it’s swetened. And stores could order pallets of 100 bottles, and could order a pallet of sweet, a pallet of unsweet, or a pallet of assorted (50 of each). Pallets are labeled accordingly. > > My first day on the job, the van was already loaded up with three pallets, labeled one of each type. I was ready to drive off when my supervisor got a call from the bottling factory. > > “Uh, we got a problem,” the bottling guy said. “I realized after all those pallets were loaded that the bottle-labeler is messed up, and all the bottles have blank labels.” > > “Okay,” my boss said. “We’ll send them back and you’ll relabel them.” > > “Well, there’s another problem,” the bottling guy continued. “I noticed when the pallets got their own labels, each one got an incorrect label. You definitely have a pallet of sweet, one of unsweet, and an assorted, but none of them have the right label.” > > “Damn. Which is which?” > > “Uh, I forget.” > > My boss hung up. “First thing is, we fire that dude. If we can figure out which pallet has sweet tea and which has unsweet tea, we can at least get those relabeled. Then we’ll have to figure out how to salvage the assorted. Problem is, we’re gonna have to keep opening and tasting bottles of tea till we find the pallet with sweet and unsweet, and that’s gonna take awhile and might waste a lot of bottles.” > > “There’s an easier way,” I said. “I’ll get all the pallets relabeled by opening and tasting just a single bottle.” > > What did I do? > > Bonus question: is the assorted pallet a loss? If not, how can we salvage it? ---
**Author:** ![Spoons](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spoons/32/3141_2.png) [@Spoons](https://boards.straightdope.com/u/Spoons)\ **Post date:** [January 25, 2020, 6:12am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/7 "2020-01-25T06:12:00Z")
Once I read the OP, I immediately thought of a logic puzzle that I encountered when I was about 13. I eventually solved it, but it took me about three or four weeks to do so (hey, I had school and homework and sports, so I couldn’t do it full-time). Still, it’s the most challenging logic puzzle that I’ve ever encountered, and I’ve done many. It’s known as “the Zebra Puzzle,” or sometimes as, “Who Owns the Zebra?” [Wikipedia has it](https://en.wikipedia.org/wiki/Zebra_Puzzle): > [@](#): > > The following version of the puzzle appeared in _Life International_ in 1962: > > 1. There are five houses. > 2. The Englishman lives in the red house. > 3. The Spaniard owns the dog. > 4. Coffee is drunk in the green house. > 5. The Ukrainian drinks tea. > 6. The green house is immediately to the right of the ivory house. > 7. The Old Gold smoker owns snails. > 8. Kools are smoked in the yellow house. > 9. Milk is drunk in the middle house. > 10. The Norwegian lives in the first house. > 11. The man who smokes Chesterfields lives in the house next to the man with the fox. > 12. Kools are smoked in the house next to the house where the horse is kept. > 13. The Lucky Strike smoker drinks orange juice. > 14. The Japanese smokes Parliaments. > 15. The Norwegian lives next to the blue house. > > Now, who drinks water? Who owns the zebra? > > In the interest of clarity, it must be added that each of the five houses is painted a different color, and their inhabitants are of different national extractions, own different pets, drink different beverages and smoke different brands of American cigarets [sic]. One other thing: in statement 6, right means _your_ right. > > — _Life International_, December 17, 1962 You could swap out the cigarettes for something more innocent like cookies (“The Oreo eater drinks orange juice,” or “The Japanese eats Fig Newtons,” for example), if you don’t want to remind your correspondent of things that tend to be forbidden in prisons. Just don’t get confused, and keep them all straight: Lucky Strike = Oreos Parliaments = Fig Newtons Kools = Chocolate chip cookies etc. But it’s a good, challenging logic puzzle, and it can be solved. Like I said, I did it. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [January 25, 2020, 6:28am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/8 "2020-01-25T06:28:49Z")
Great input everyone, thanks. Follow-up question (which has nothing to do with the puzzles themselves): I’ve thought of making the challenge even more interesting by offering monetary prizes or some other reward (like commissary snacks or items, which can be bought for inmates online via a prison website system) - something like, \*“I will send you a super-tough riddle or puzzles on a regular basis, and if you can solve them, you get a $5 or $10 prize” \*- (money can be put into an inmate’s commissary account online via prison website, too) - is this a good way to add intrigue to the challenge, or is it something that will backfire horribly in some unforeseen way, maybe even be illegal? ---
**Author:** ![Spoons](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spoons/32/3141_2.png) [@Spoons](https://boards.straightdope.com/u/Spoons)\ **Post date:** [January 25, 2020, 7:17am UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/9 "2020-01-25T07:17:16Z")
> [@Velocity](#): > > Great input everyone, thanks. > > Follow-up question (which has nothing to do with the puzzles themselves): I’ve thought of making the challenge even more interesting by offering monetary prizes or some other reward (like commissary snacks or items, which can be bought for inmates online via a prison website system) - something like, \*“I will send you a super-tough riddle or puzzles on a regular basis, and if you can solve them, you get a $5 or $10 prize” \*- (money can be put into an inmate’s commissary account online via prison website, too) - is this a good way to add intrigue to the challenge, or is it something that will backfire horribly in some unforeseen way, maybe even be illegal? As a lawyer who has been to the local jail and who has heard from inmates before as to how important their commissary (in the local jail, it is just known as “canteen”) accounts are to them, I’d say that’s not a bad idea. Certainly, locally, anybody can top up a particular inmate’s account if they wish, and many times, the inmate’s family and/or friends will do so, if able. However, you want to check with prison authorities first. It’s one thing for an inmate’s mother to put $10 in her son’s canteen account; it seems to me that it is another thing for an inmate to win a prize of some sort from a third party on the outside, even if the prize is only $10 on the inmate’s canteen account. Speaking non-professionally, I like the idea. Speaking as a professional, I’d say that this is something you need to ask the authorities about. They’re the people who can tell you whether this might backfire, or be illegal. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [January 25, 2020, 12:29pm UTC](https://boards.straightdope.com/t/i-need-tough-riddles-and-puzzles/846930/10 "2020-01-25T12:29:51Z")
The prize is an interesting idea, but I’d worry that psychologically it could turn the puzzle from pleasure into work. External rewards can make activities less intrinsically rewarding. Not saying don’t do it, but think about the effects before you do.