UPDATE: The game Brandscape is not active anymore.

Here is a nice pop-culture puzzle quiz by our friends at Funding Circle. They have created a colorful painting with 60 hidden references to famous brands in it, which you must find and recognize correctly. The puzzle is fiendishly hard but really fun to solve. To play it, just click the image below. Good luck!

Mathematical Puzzles: A Connoisseur’s Collection


Mathematical Puzzles: A Connoisseur’s Collection by Peter Winkler is not your casual puzzle book. Even though most of the problems inside are easy to formulate, many of them require extensive mathematical background and well-developed analytical thinking. If you possess these two qualities, however, you will certainly enjoy this book. The puzzles are hard, the solutions are beautiful and the explanations are very well-written. The book contains over 100 puzzles that are split into different categories – Insight, Numbers, Geometry, Geography, Algorithms, and others. In order to give you an idea of what to expect, I have selected several puzzles from the book which represent its overall level.

1. Given 10 red points and 10 blue points on the plane, no three on a line, prove that there is a matching between them so that line segments from each red point to its corresponding blue point do not cross.

2. A phone call is made from an East Coast state to a West Coast state, and it’s the same time of day at both ends. How can this be?

3. The hour and minute hands of a clock are indistinguishable. How many moments are there in a day when it is not possible to tell from this clock what the time is?

4. Associated with each face of a solid convex polyhedron is a bug that crawls along the perimeter of the face, at varying speed, but only in the clockwise direction. Prove that no schedule will permit all the bugs to circumnavigate their faces and return to their initial positions without incurring a collision.

MP:ACC is one of the most valuable puzzle books in my collection. If you are up to the challenge it offers, you owe yourself a favor to buy it. Even if you don’t feel too confident in your abilities to solve the problems in the book, you can still get it and study the solutions. And if you need more mathematical brilliance, you can check out Peter Winkler’s other puzzle book, Mathematical Mindbenders.

  • 15 years and up
  • math-heavy, difficult puzzles
  • ingenious and elegant solutions
  • various categories, including geography!
  • great explanations and notes by the author


* This post contains affiliate links. We may receive a small compensation if you make a purchase.

Free Rice

What is better than solving problems and learning new things? Doing exactly that, while fighting the hunger in Africa! “Free Rice” is a website, on which you choose a topic (vocabulary, science, math, etc.), and every time you answer correctly to a question, you contribute 10 grains of rice to people who need them. By clicking the banner below, you will be redirected to Just make sure to disable your ad-blockers, since hiding the (non-intrusive) ads may prevent you from accumulating donations.

The Evolution of Trust

Game Theory is an intriguing subject in Mathematics, with various real-life applications. Even though many people have heard about the “Prisoner’s Dilemma” – one of the most famous problems in the field, few have delved deeper into the theory. Fortunately, Nicky Case (also a creator of “Parable of the Polygons”) is here to help again, by educating us in a fun, engaging manner. Check out his quick, 30 minutes introduction to Game Theory by clicking the image below.

Donald “Rusty” Rust

Donald “Rusty” Rust is an American artist, who has created over 15000 paintings in a variety of styles. Even though he is famous mostly for his pin-up artwork, his optical illusions are some of our all-time favorites. In this special interview, he shares with us his thoughts on painting, op art, and everything which drives him forward in his long and successful career. If you like Rusty’s artwork, you can order some of it through his official store on Etsy.


Q. Hello Rusty. This is such an interesting nickname. I assume it is derived from your last name?

A. Having been born with red hair and having the name, Rust, made the nickname, “Rusty”, come easily!

Q. How did you get into painting? Was it a hard choice to devote your life to being an artist?

A. My painting career probably began one day when my grandfather, who was an artist, looked at a small drawing I had done. I must have been four or five years of age. He put me on his lap and took a drawing pencil, which he firmly pressed onto my drawing, showing me how to make my drawing more effective. Of course, that comes with confidence, something I did not yet have. My school years found me doing most of the posters within the school. After graduation, I learned that painting signs could supply enough income, so, that went on until I was about forty-nine years old. Then, I began doing portraits, which eventually, led into other subject matter. No more sign painting!

Q. Apart from your grandather, which other famous artists have inspired and influenced you?

A. Well-known pinup artist, Gil Elvgren, did work I admired. His guidance and help played a big part in the quality of my work. Bobby Toombs, Gil’s apprentice, also offered a great deal of help.

Q. Art trends have been changing a lot throughout the years. What do you think of contemporary art and how do you compare it with the more traditional art forms?

A. Times change and I welcome new ideas and styles of painting. Years ago, artists did not have projectors, air-brushes and digital images that could be altered with a click of a mouse. Always interesting!

Q. You have been creating all kinds of compositions – pin-up girls, landscapes, portraits, illusions… What is the reason to be so versatile and what type of work are you currently focused on?

A. I’ve been versatile, mainly because I continually look for subject matter that “catches on”. Everything I tried provided a variety. My studies were geared primarily toward realistic painting. Over the years, my interests have changed. Now, I am doing more fantasy-type work, which allows for more creativity and originality.

Q. What is your secret for creating such amazing optical illusions? Do you first start with the hidden image and then try to conceal it, or first draw the main picture and then incorporate the illusion inside?

A. I have no formula for the creation of illusion images. My main concern is to mislead or trick the viewer. A good example of that is my painting, “The Hidden Tiger”, which was done when camouflage art was so popular. Viewers were accustomed to search for an animal or something that is hidden within the scene. They could not find the hidden tiger. I had tricked them by hiding the lettering, “THE HIDDEN TIGER”, which was the stripes on the tiger. Sometimes, it is necessary to turn the image upside down to see the solution. 

Q. Sounds like it requires lots of preparation and inventiveness. How much effort and time does it take to create such optical illusion, starting from the concept up until the finished product?

A. Some paintings can be done in a short length of time, while others take longer.  Often, more time is spent on planning than painting. I’m usually regarded as a rather fast painter, but, I spend several hours on research and planning. I try to incorporate the elements of good art… things like, ideas, drawing accuracy, composition, tonal planning. color, etc.

Q. Our final question about illusions – which one of your illusions is your favorite?

A. One of my favorite illusions is “The Mirror”. I’ll not explain it as that would take away all the fun!

Q. Finally, what are your hobbies and what do you like to do in your free time?

A. My free time is roaming the jungles of Florida and getting good photos of scenic and wildlife subject matter. Those photos are often used as a reference for my paintings.

Q. Sounds like a terrific pastime! Thank you for the interview Rusty, we don’t want to take any more of your jungle exploration time.

A. Thank you, Puzzle Prime.

Smart Eggs


Smart Eggs are maze type puzzles created by the Hungarian inventor Andras Zagyvai. The basic idea is to navigate a plastic stick from the top of an egg to its bottom, pushing, pulling and moving the stick around various holes and tunnels carved in it.

The original six 1-layer Smart Eggs are extremely simple to solve and targeted towards very young children. There is only one natural path the stick can take and you simply have to follow it. The eggs are also fairly small and initially may look a bit underwhelming. The designs however are beautiful and the construction is solid. Despite the low difficulty level and lack of hard challenge, the 1-layer Smart Eggs are fun to play and fidget with, both for kids and adults. Collecting them all results in a wonderful shelf collection.

The 2-layer Smart Eggs are the bigger, better, harder version of the original 1-layer Smart Eggs. The goal remains the same – navigate a stick from the top of the egg to its bottom. The collection consists of three Dragon Eggs – blue, red, and black, listed in according to their difficulty level. The first thing which makes impression is the beautiful art – on every egg there are three dragons depicted, no two of them the same. These toys have much higher quality than the original Smart Eggs – they are around twice the size, come with metal sticks, plastic stands, and much more intricate designs. Inside every egg there is a core which can rotate and also slide up and down, creating many possibilities for the stick’s movement. Even though the blue egg is fairly straightforward to solve, the red and the black ones can pose a real challenge. The 2-layer Smart Eggs have high replay value and you will probably find yourself coming regularly back to them. They are fun, smart, and highly recommended puzzles.

  • 6-8 years and up
  • 1-layer and 2-layer options
  • various beautiful designs


* This post contains affiliate links. We may receive a small compensation if you make a purchase.


Constant learning is important, but often times a very boring process. To tackle this issue, the guys from Kurzgesagt have started releasing new, engaging, educational videos every few weeks. Some of the puzzling topics they cover are A.I. (artificial intelligence), finance, the Big Bang, and many others. Both the quality of the production and the content itself are very high, so we recommend all of our friends to watch these videos.

So, do not waste time and go check Kurzgesagt’s website by clicking the image below, or simply visit the official YouTube channel.


FLEB is a passionate puzzler and a popular YouTuber. To his YouTube audience, he regularly presents various interesting puzzles he has collected over the years. FLEB is a former TOP10 finisher in the US Puzzle Championships and also a regular participant in the MIT Mystery Hunt. Recently, he released his first puzzle video game – RYB. You can see FLEB’s favorite puzzles on his official YouTube channel.


Q. Hi FLEB! Is this your real name? If not, where does it come from and what does it mean?

A. Hi, my real name is Paul Hlebowitsh. At MIT, people oftentimes call each other by their Kereberos (computer system) usernames. Mine was “phleb”, which when pronounced sound like FLEB! That’s where that comes from.

Q. When and how did you get into puzzles?

A. When I was young, I would often check out books on brainteasers and puzzles. I was a big fan of the “Encyclopedia Brown” books and there was a series of “Clue” books that were similar. When I was in high school, I was lucky enough to know some people who were involved with the MIT Mystery Hunt and I was able to solve it remotely through the internet with their team!

Q. Talking about the MIT Mystery Hunts, what is the name of your team? How did you choose your teammates?

A. The small puzzle team I hunt with is mostly friends of mine from college, who also got into puzzles. We use a bunch of different names, but the most recent one was “The Sweatiest Tryhards”.

The big Mystery Hunt team that I’m a part of is called “Death and Mayhem”, which started way before I joined it. It’s the merger of two teams “Death From Above” and “Dr. Teeth and the Electric Mayhem”. I joined “Death From Above” around 2008, but it was around for a long time before that. I’m not sure where the name comes from!

Q. How many puzzles do you have in your collection?

A. Oh gosh, I’m not sure. Probably close to a thousand, but I haven’t counted. I know I own around a hundred Hanayama puzzles alone!

Q. That’s a lot, we definitely need to catch up here! Do you remember the first puzzle you ever got?

A. My first puzzle was a Rubik’s cube, which my parents bought me for my birthday when I was young. It’s a good one to start with!

Q. Which is your favorite mechanical puzzle?

A. For my wedding, a bunch of my puzzle designer friends built me a custom 4’x2’x2′ puzzlebox, which is simultaneously the biggest puzzle I’ve ever had to solve, along with the most complicated. It includes a working telephone which plays messages after you’ve solved individual puzzles!

Q. Sounds very inventive. And what about your favorite brain teaser, or game?

A. For brainteasers, I think I’m going to cheat this question a little bit and choose a collection. I think “What is the Name of this Book?” has the best brainteasers out of any book I’ve seen. They’re all in the “liars and truth-tellers” types of brainteaser, but he slowly guides you to answering ones about people who answer randomly and in a language you don’t understand.

When it comes down to games, I really like “The Talos Principle”. I think that’s the best puzzle game I’ve ever played. Then I think it’d be “The Witness”, “Linelight”, “The Room”, and “Hexcells” in some order.

Q. You are a TOP 10 finisher in the US Puzzle Championship, which is a great achievement. What does your preparation for puzzle championships look like? Do you have any tips for others who are getting into competitive puzzle solving?

A. Mostly it involves creating and solving puzzles. If you want to get into competitive logic puzzle solving, one of the most important aspects is learning how to create logic puzzles! Creating puzzle is a great way to understand new logic puzzle types.

Q. How did you decide to start making youtube videos? Did you expect to make your channel so popular?

A. I wanted to share my joy of puzzles with others! I didn’t expect it would be so popular at all!

Q. What are your future plans for it?

A. I’d love to cover more aspects of puzzles in the future, such as puzzle history and design, but I’d also like to cover some brainteasers and more puzzlehunt puzzles.

Q. We are looking forward to this. What other hobbies do you have, apart from solving puzzles and playing board games?

A. I really like Rocket League! I’m terrible at it, but it’s fun. In the fall, I also love college football. Almost every Saturday during the fall I watch a game or two!

Q. As a last question, what would you recommend to our readers, which want to improve their overall analytic and problem solving skills?

A. Puzzles are a great way to get entertainment!

Q. We completely agree with that. Thank you for the interview, FLEB.

A. Happy puzzling Puzzle Prime!

The Master Theorem

In case you have never heard about “the secret society of puzzle solvers” at The Master Theorem, then get ready to face about 50 of the most creative, challenging and original puzzles you can find on the web. Even though the website rarely has been updated in the last few years, it can offer tens of hours of problem solving to all newcomers. In order to sign up and explore everything TMT has to offer, you must first complete one of the numerous puzzles posted there. An easy one you can start with is “Old McDonald”, which can be solved using this… SPOILER.