Cooltools by KKModify

2026-06-02 00:00:00

Memorable estimates

Rules of Thumb

I’m a big fan of rules of thumb. Like: “Count the number of times a cricket chirps in 15 seconds, and add 37. That’s the temperature in Fahrenheit.” They are great estimating tools. At the Whole Earth Catalog we first published Tom Parker’s collection of these portable estimates, soliciting others from readers. I suggested a few rules of my own, which made their way into one of Parker’s later books. Since I remember — and use — a number of these rough recipes, I have always regretted that the books were out of print. If ever there was knowledge ideal for the web, rules of thumb are it. Tom Parker has recently digitized all the rules he has collected. He posts one old rule per day, and one new one suggested by readers. As the rules are tagged over time to make searching easier, we’ll finally have the world-wide database of guesstimates that short-cut-takers like myself have always wanted.

You can find inexpensive used copies of the books, Rules of Thumb, and Rules of Thumb 2, but the web site really is a much better way to use and discover these. Parker has refined his explanation of what rules of thumb are, and why they are cool tools. He writes:

“A rule of thumb is a homemade recipe for making a guess. It is an easy-to-remember guide that falls somewhere between a mathematical formula and a shot in the dark. Rules of thumb are a kind of tool. They help you appraise a problem or situation. They make it easier to consider the subtleties of the topic at hand; they give you a feel for a subject. A rule of thumb is not a joke or a ditty. It is not a Murphy’s Law. Murphy says that things will take longer than we think; a rule of thumb says how much longer. While a proverb says that a stitch in time saves nine, a rule of thumb says to allow one inch of yarn for every stitch on a knitting needle.”

I’ve spent a lot of time reading through these over the years. I now subscribe to the Rules of Thumb RSS feed from Parker’s site. My new rule of thumb: “One in 25 rules of thumb will be useful to you.” YMMV, but I find that a pretty good hit rate. — KK

• The best way to make money in residential real estate is to buy the worst home on the best street.
• The moon covers half a degree of sky.
• When digging a grave by hand, haul away 17 wheelbarrow loads of dirt and pile the rest by the hole. You will have just the right amount to backfill.
• For marketing purposes, elderly consumers think they are 15 years younger than they actually are.
• The price of a telescope increases proportionately to the cube of the lens diameter.
• Recovering an unused physical skill takes one month for each year of layoff.
• If you walk into a bar where a lot of people wear baseball caps, it’s a good place to sell lottery tickets.
• Eclipses often come in pairs. A lunar eclipse is followed frequently by a solar eclipse two weeks later, and vice versa.
• If the cats aren’t sleeping on the radiators, turn down the heat.
• One chemical toilet serves 15 employees per week.
• It takes two minutes for the sun to drop out of sight once it touches the horizon.
• If a woman can walk around during contractions, she is not fully dilated.
• When you are working in the vicinity of high voltage, keep 1 foot of distance between you and the power source for each 1,000 volts. For instance, stay 13 feet away from a 13,000 volt power source.
• You have a 50 percent chance of surviving overboard in 50 degree water for 50 minutes.
• Spring moves up in altitude 1000 feet per week
• Ten people will raise the temperature of a room one degree per hour
• If a speech takes 15 minutes in a dry run, it will take one third longer on the actual event.
• Rental property should sell for 100 times the monthly rental income.
• Double the height of a 3-yearold to determine his or her adult height.

How to memorize anything

Super Memory, Super Student

Harry Lorayne has been teaching ancient principles of memorization for 50 years. They really work. My dad taught me these when I was a kid and I still rely on them. At first the methods seem gimmicky, but they soon become habit. The techniques are well proven (some are thousands of years old) and will benefit anyone. However in this book Lorayne aims at students, providing them ways they can use easy tricks to tackle common school memory tasks. He has a system for turning numbers into words so you can remember numbers and dates as well. Imagine how much more efficient you’d be if your memory was just five percent better, and howmuch easier your life would be if everyone else’s improved. —KK

• Every high-school student I’ve spoken to knows about the acronym FOIL, which is a memory aid for remembering how to attack an algebraic equation: Firsts, Outers, Inners, Lasts. (More on this in the algebra section in chapter 20.) And I’ve never met a doctor or a medical student who didn’t remember the cranial nerves (olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory, glossopharyngeal, vagus, accessory, hypoglossal) by reciting the couplet
  
  On Old Olympia’s Towering Top
  
  A Finn And German Vault And Hop.
  Professors have helped medical students learn the layers of the scalp by suggesting that the word “scalp” itself might remind them of skin, close connective tissue (cutaneous vessels and nerves), aponeurosis (epicranial), loose connective tissue, pericranium.
• I’ve said it so many times, it’s been copied so many times, I may as well say it again: The “three R’s” cliche – reading, ‘riting, ‘rithmetic – should be four R’s. The first R should be remembering. Because without that first R, you can’t read, write, or do ‘rithmetic! All education is based on remembering. I know of no high school or college subject that doesn’t require lots of memory work.
• In order for you to remember any new thing it must be associated, in someridiculous way, with something you already know or remember.
• Desecrate – “to profane a holy place; to treat a sacred thing irreverently”: You’rein a desert and see a gigantic crate — desert crate. It’s a sacred thing (perhaps a halo is over it), but you kick it and so forth — treat it with disrespect, irreverently. (Dat’s a crate would also do.)
  Atrophy – “to waste away from lack of use”: A trophy or I throw fee will remind you of the pronunciation. Connect one of them to the meaning of the word. Perhaps visualize a trophy (a gigantic loving cup or statue) wasting away shrinking) because no one ever uses it (see it covered with dust and spiderwebs).
  
  Relegate – “to send to a lower position”: You roll a gate downward, sending it to a lower position. Be sure you actually see that.

Ultimate recovery

How to Find Lost Object

In my household I am Mr. Find It. I rarely if ever lose things myself, and have become the go-to guy to find what others have lost. Over the years of finding things, I have evolved a set of principles very similar to those laid out in this very simple book. This method really works.

You can read this book for free online. That way you’ll never lose it.

But some people like the laminated-paper-pulp form to give as a gift. While there is more in the slim book, none of the extra is essential. Still, it’s a handy quick reference. — KK

Principle Ten

The Eureka Zone

The majority of lost objects are right where you figure-once you take a moment to stop and figure.

Others, however, are in the immediate vicinity of that place. They have undergone a displacement-a shift in location that, although minor, has served to render them invisible.

Some examples:
A pencil has rolled beneath a typewriter.
A tool has been shoved to the rear of a drawer.
A book on a shelf has gotten lodged behind other books.
A folder has been misfiled, several folders away from where it belongs.
Objects are apt to wander. I have found, though, that they tend to travel no more than eighteen inches from their original location. To the circle described by this eighteen-inch radius I have given a name. I call it the Eureka Zone. With the aid of a ruler, determine the Eureka Zone of your lost object. Then explore it. Meticulously.

Once a week we’ll send out a page from Cool Tools: A Catalog of Possibilities. The tools might be outdated or obsolete, and the links to them may or may not work. We present these vintage recommendations as is because the possibilities they inspire are new. Sign up here to get Tools for Possibilities a week early in your inbox.

2026-06-01 00:00:00

Life in ancient times

Most sources of AI-generated content do not warrant a second visit. The only AI-generated content I have been returning to are two YouTube channels that use AI to reconstruct history. The first one, Majestic Studios, recreates daily life in now legendary ancient cities as seen through time. I learned a lot, for instance, by following the development of Paris from 259 BC till the present. This same creator (a British bloke, Jonathan Laramime) created a synthetic character named Chloe, styled as an influencer in LA, who pretends to be a time-travelling tourist. Chloe is very believable. She wanders the streets in ancient times taking selfies and being wowed by the cultural norms. Chloe’s valley girl reactions to the ancient world is accessible and entertaining, but also historically accurate, which has made the channel Chloe VS History a viral hit. Recreating history is the perfect job for AI, and I expect these channels to be the first of many, as other history buffs create their own improved versions. — KK

Beautifully designed two-player card game

I bought the Desperate Oasis card game solely because the retro design is gorgeous — vintage orange-and-cream illustrations of camels, scorpions, jackals, and chameleons that look like they were pulled from a 1920s matchbook art. The fact that it’s actually fun to play is a bonus. Two players battle for control of five desert oases by playing animal cards on either side, using palm trees to boost values, and triggering special powers (the Deathstalker Scorpion destroys the weakest card; three Jackals create a bonus space). A round takes about 15 minutes, and a full game is three rounds. — MF

Theatrical releases you can stream

Every weekend I set out to figure out what’s in theaters that I can also watch from home. But between all the streaming services and web directories, I end up spending more time searching than watching. JustWatch.com used to solve this for me, but lately it feels complicated and sometimes inaccurate. It’s a made-up problem that doesn’t really matter but is genuinely annoying. My current fix is this IMDB list of theatrical releases you can stream or rent, and it seems to actually stay updated. — CD

Cheap living in China

Chinamaxxing is fashionable right now. One guy moved his family from America to China and gives an account of how much it costs to live in the middle class in China. His video report, “I Left the US for Shenzhen, China – Here’s How Much it Costs” ignores all the political aspects of living in China and merely focuses on the economic. Right now very few westerners will want to make the political tradeoffs to move to China, but this report will reveal a bit about how middle class Chinese are actually living, and gives a more realistic portrait of China today. — KK

Oddly satisfying tree stump removal videos

Uproot Excavator is a YouTube channel devoted entirely to one thing: tree stumps being yanked out of the ground by heavy equipment. The arm of an excavator, fitted with a pincer-like attachment, clamps onto a stump, rips it out along with a massive clump of roots that must weigh several hundred pounds, shakes the dirt loose, and sets the whole thing aside next to a fresh crater in the earth. That’s it. Hundreds of short videos, all basically the same removal over and over. I find it weirdly hypnotic and deeply satisfying to watch. — MF

Ten-minute skills for the rest of your life

This Reddit thread asks what a person can learn in 10 minutes that will be useful for life, and the top-voted answer is using your hand span, thumb to pinky, as a built-in measuring tool. Mine is 7 inches, which I will now never forget. The other favorites in the thread are worth sharing for your relationships and your nervous system: “Never explain yourself to people committed to misunderstanding you.” Before responding in an argument, scan your body and take a slow nasal breath to notice fight or flight before you speak. Then speak calmly. “‘No, I can’t’ is a full sentence. You don’t owe anyone a 10-minute TED Talk about why.” — CD

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2026-05-30 00:00:00

Get A Calendar of Wisdom

A Calendar of Wisdom is a daily reader Tolstoy assembled in the last decade of his life. Each entry pairs several short quotes from someone like Epictetus, Buddha, Marcus Aurelius, or Pascal with a paragraph of Tolstoy’s own commentary. He intended it to be read one page a day, and read repeatedly every year for the rest of the reader’s life.

Core Principles

1. One wise idea a day is enough

Tolstoy thought one wise idea a day was enough, and he laid the book out to match. You read a quote, you read his short reflection on it, and that’s it for the day.

2. False knowledge is worse than ignorance

The useful skill is sorting what’s necessary to know from what isn’t. If you don’t know something, you can learn it. If you wrongly think you already know it, you can’t.

3. Love is the project worth a whole life

Tolstoy believed creating more love between people and reducing what divides them was the only project worth a whole life. He put money and status well below it.

4. The same problems, two thousand years ago

The contributors include Epictetus, Marcus Aurelius, Lao Tzu, the Buddha, Pascal, Emerson, and Tolstoy himself. You’ll realize others have had the same problems you did two thousand years ago and wrote down what they figured out.

Try It Now

1. Read one entry from A Calendar of Wisdom (or any wisdom book) every morning before checking your phone, for a month.

2. Make a list of what you read, watched, and listened to this week. Cross off everything that was not necessary to know. Look at what’s left.

3. Think of one person you’ve lost touch with or fallen out with. Send them a message today.

4. Pick one of the philosophers Tolstoy quotes (Epictetus, Marcus Aurelius, Lao Tzu, Pascal, the Buddha) and read one short book by them this month.

Quote

January 23

Among all sins, there is one which completely opposes the major blessing of human life, which is your love for your brother: there is no worse sin than to destroy this major joy of life, by feeling rage and hatred for your brother.

Seneca, a wise man from Rome, said that when you want to escape from your rage, when you feel that it grows, the best thing to do is to stop. Do not do anything: do not walk, do not move, do not speak. If your body or your tongue moves at this moment, then your rage will grow. Rage is very harmful for all people, but it is most harmful for the man who experiences it.

“An evil person damages not only others but himself.” — After SOCRATES

“Your enemy will pay you back with rage, will make you suffer, but the biggest damage to you will be caused by the rage and hatred existing in your heart. Neither your father, nor your mother, nor all your family can make you more good than your heart can when it forgives and forgets its abuse.” —DHAMMAPADA, a book of BUDDHIST WISDOM

Your rage cannot be justified by anything. The reason for your rage is always inside you.

Book Freak is published by Cool Tools Lab, a small company of three people. We also run Recomendo, the Cool Tools website, a YouTube channel and podcast, and other newsletters, including Recomendo Deals, Gar’s Tips & Tools, Nomadico, What’s in my NOW?, Tools for Possibilities, Books That Belong On Paper, and Book Freak.

2026-05-29 00:00:00

A New Stopover Program for Munich

I’ve written before about the advantages of an airline stopover program to get two vacations on one trip, but now there’s a new one to add to the list. Lufthansa has built one into their online reservation system to let you stay up to one week in Munich on your way to somewhere else. I had a good time there a couple of years ago and when it’s not Oktoberfest, you can walk right into the Hofbrauhaus and get a table. See more info here.

Free National Parks Entry

No, not the USA ones that have suffered price hikes and budget cuts the same year, but the often less crowded Canadian ones are offering free entry to everyone who shows up during the period when kids are out of school. This is valid from June 19 to September 7. That’s not all either. Go here to see details about getting 25% off on overnight park stays, discounts at museums, and reduced price tickets for those under 18 on Via Rail.

Shakira Beats Spain’s Tax Grab

I reported back in 2023 that Shakira paid the Spanish government 7.3 million euros in a settlement about back taxes to avoid jail time. They fined her for more than that though for a previous year (2011), saying she had spent more than 183 days in the country and was therefore a tax resident. She appealed and just won handily: the government now owes her 60 million euros including interest. They could only prove she was in the country 163 days and didn’t demonstrate that it was the base for her business.

Dissecting the “Schengen Shuffle”

Most non-EU nationalities can only stay in Europe 90 days out of 180, which leaves a lot of nomads looking for creative ways to stay on the continent (or nearby) beyond that. Many spend that time in countries that aren’t part of the zone but are still on the continent (or nearby), which necessitates a “Schengen Shuffle.” Apparently the term is becoming mainstream because last week it warranted this article in CNN.

A weekly newsletter with four quick bites, edited by Tim Leffel, author of A Better Life for Half the Price and The World’s Cheapest Destinations. See past editions here, where your like-minded friends can subscribe and join you.

2026-05-28 00:00:00

Gordon Tebo is a singer/songwriter living outside of Chicago. He recently released his new album, “Exotic Fears”, which served as a sort of exorcism of anxiety and grief.

PHYSICAL

• An acoustic piano. Not a digital piano. Nothing you have to switch on: it’s always on—that’s the feature! It doesn’t even have to be a piano. A guitar works great, too. Even if you don’t know how to play an instrument, it doesn’t matter. The presence of the instrument in your apartment, house, life, is enough. A friend comes over, sits down and plays a song. Kids come by and noodle mindlessly. It’s a piece of furniture, and it’s not going anywhere. It’s not a liability: it’s a major organ in the living organism you call home. Get one, used. Play it first before you buy it. Get the one that feels right. It will change your life.
• The Peak Design Travel Backpack 45L. Good backpack design is like conceptual origami. How did they seemingly include every conceivable useful feature, spanning functionality, security, and accessibility, into a package that looks sleek and feels great? It’s masterful. I just went to Philly on a 3 night trip and it was overkill. I could travel for a week in this thing comfortably. I want to travel even more than I already do because it makes travel fun and freeing. Thoughtfulness, resourcefulness, and thoroughness: it’s what makes things great.
• My beater 2014 Toyota Highlander. I had been contemplating buying a newer car on the grounds that this car is now over 100k miles, has taken some hits, doesn’t have the best gas mileage, the tech is ancient, the turning radius is terrible, and the back hatch takes forever to actually open on its automatic mode. But then I got thinking: I drove my family across the country on a move. I took my aging and sick dog on its final car ride. I drove my second newborn home from the hospital in it. I can bang it up and it doesn’t care. I don’t stress about this car. No one probably wants to steal it. No one even notices it. In fact, someone drove into it at full speed because they didn’t see it (they were on their phone). I thought it was totaled but it came back to life and I swear it drives better now, and maybe even loves me back at times.

DIGITAL

• Bear (notes app). Here’s where I do all of my writing. Lyrics, random thoughts, poems, beliefs, dreams, recipes, drafts, everything. It’s nothing special, but it works. It works because it’s not trying to be anything more than a good notes app. It’s minimal yet not lacking features. It’s sleek yet it’s not trendy. Everything I’ve done that took a little bit of planning and turned out great in the past 5 years started right here in Bear.
• Infinite Loops podcast. Like all podcasts, you kind of have to forgive the host. They don’t know who’s listening, or how many times they’ve listened to one of their episodes. They often repeat the same things every episode, tell the same stories, and you know what they’re about to say before they start talking. But that’s not what makes a podcast. The guests make it or break it, and Infinite Loops has great guests that span all sorts of disciplines and offer all manner of thoughtful opinions and measured ideas. Their heads are screwed on tight but they still provoke deep and useful thought. And the host is pretty good, too.

INVISIBLE

A sense of humor.

“Humor and self-righteousness are mutually exclusive” … a classic Alan Watts observation.

This quote is a useful tool for being alive right now. I can get mad that things aren’t going my way or the world is spinning out of control more than yesterday, and my feelings are valid, of course. But one has to balance out those feelings with awareness. And the funniest thing a person can say is what they firmly believe to be true. That’s the funniest damn thing! Try it sometime with someone you trust and love. Once you out it, you pop the bubble in your mind that was holding it all together and you realize you don’t actually know anything other than how you feel inside right now. And that always makes me feel better. Laughing feels great too.

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2026-05-27 00:00:00

FROM SLOBBERY ROBOTS AND ALIENS WITH BRIEFCASES TO DIDGERIDOO LESSONS

Alien Invasion in My Backyard: An EMU Club Adventure
by Ruben Bolling
Andrews McMeel Publishing
2015, 112 pages, 5.3 x 8 x 0.4 inches

Buy on Amazon

TV will tell you the truth is out there. Decades ago folks would warn you to “Keep watching the skies!” But kids know the truth: The mysteries aren’t out there, they’re right here. They are in every bump from the attic, that weird locked door in the basement, and, especially, the often mystifying backyard. Kids know that’s where the real mysteries lie, and we’re all lucky that Ruben Bolling knows it, too.

Alien Invasion in my Backyard, the first in the EMU Club series, is a fun and ridiculous (in just the right way) story of the creation of the Exploration Mystery Unbelievable Club. The book itself is intended to be the Official Report of their first mystery and written by eleven year-old President Stuart Tennemeier who, other than planning on a growth spurt in college, is planning to document all their amazing adventures. His best friend, CEO Brian, and his little sister Violet (no title because Mom makes them let her join) join him to solve all of life’s important mysteries. And we can’t forget Sergeant at Arms Ferdinand, Stuart’s loyal dog who proves critical to cracking the case. As an Official Report the reader gets direct access to the EMU Club files, including photos of their whole adventure lovingly taped to the lined graph paper it’s printed on. This is fresh from the brave pioneers themselves and you’ll read and see every detail, from slobbery robots and aliens with briefcases to didgeridoo lessons.

Ruben Bolling is the pen name of the creator of the awesomely acidic Tom the Dancing Bug and a finalist for the 2016 Herblock Award for Editorial Cartooning. This, his first work for kids, is a light, charming read that one can only hope gets into the hands of many a little one thirsting for adventure. As a recovering child who looked for mystery behind every door but mostly found it in books, I can tell you I enjoyed reading every moment of this book and cannot wait until I can share it with my own little adventurer. Once he learns how to talk, find important clues, and play the didgeridoo, of course. – Rob Trevino

BAKE THE MOST GHOULISH SWEET TREATS YOU’LL EVER EAT

Deceptive Desserts: A Lady’s Guide to Baking Bad!
by Christine McConnell
Regan Arts
2016, 288 pages, 8 x 10 x 1 inches

Buy on Amazon

Take a ripened crafter, mix in a pinch of YouTube lessons on cake decorating, blend that with a humorous fascination with the macabre, and you’ve got Christine McConnell’s new cookbook, Deceptive Desserts.

Just four years ago McConnell had never even baked a cake. But she was already a professional makeup and hair stylist, an impeccable photographer (much of which she learned through YouTube), and even created her own vintage-inspired clothes. Then after seeing some online photos of beautiful cakes, she decided to take a few online lessons on cake decorating. In 2013, while perfecting her baking skills, she made a batch of life-sized chocolate tarantula treats out of Girl Scout cookies for Halloween and realized that baking the dark side was her new passion. Her list of ghoulish culinary masterpieces quickly grew, along with her Instagram account, which now has over 248,000 followers.

Books That Belong On Paper first appeared on the web as Wink Books and was edited by Carla Sinclair. Sign up here to get the issues a week early in your inbox.