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Disappearing Bicyclist – Sam Loyd (1906)

geogebra.org

31–40 of 66 posts

Re: Disappearing Bicyclist – Sam Loyd (1906)

#31
post #4

Earlier quoted context omitted.

This one includes flags as an easy hint.

The flags don't really "do" anything. In the one configuration, every flag is held by a boy. In the other configuration one boy has no flag, and there is a severed hand holding a flag.

That's actually wrong for the other configuration. In one, every boy has a flag. In the other, there's one boy with no flag, and 12 boys with flags. The appearance of a boy with no flags is an insight.

Re: Disappearing Bicyclist – Sam Loyd (1906)

#32

Part of the trick is that the boys are split into two parts and progress from more inside to more outside along the wheel. Since the unit "a boy" is based on real world experience where boys can be different sizes and especially since how much space a boy takes up in an image can vary depending on angle, we mentally accept that this mashup of different amounts of body parts adds up to "one boy" rather than thinking "…

Yeah the size of the boy half goes from say 5% to 95% around the circle, on both sides. In the 12 boys configuration the halves are paired correctly to add up to 100% sized boys. But in the other, there are 12 boys smaller than 100%, and then at 8 o'clock two 95% pieces appear together so we round them up to two. Neat illusion.

Re: Disappearing Bicyclist – Sam Loyd (1906)

#33
post #26
post #3

Unfortunately this doesn't work with banknotes ... unless you can find lots of people who are willing to accept a banknote that appears to have been torn into two pieces and then stuck together again with sticky tape, with the line of the tear being a weird curve that just happens to cross both serial numbers in roughly the same place.

That sounds like something from Martin Gardener, I definitely heard of this trick!

Yes, I believe he has a Dr. Matrix story in which Dr. Matrix attempts to do this and gets arrested.

Edit: "Sing Sing" in The Magic Numbers of Dr. Matrix.

> In desperation he did a foolish thing. He tried to make some twenty-dollar bills. His method was bizarre and surprising. With a paper cutter he sliced each of fourteen bills into two parts, cutting them neatly along the broken vertical lines on each of the schematic bills shown on the left side of Figure 4. [...]

> Unfortunately—or rather, fortunately—the United States government places duplicate serial numbers at opposite comers of every bill, and most of the numerologist's new bills therefore bore pairs of serial numbers that did not match. True, Dr. Matrix's method of making new bills was not exactly counterfeiting—he merely "rearranged" the parts of genuine bills. Nevertheless, the Treasury Department took a dim view of his work and it was not long until he found himself firmly confined within the matrix of cells at Sing Sing.

(note that although Gardner is best known as a nonfiction writer, the Dr. Matrix stories are fictional)

Re: Disappearing Bicyclist – Sam Loyd (1906)

#36
post #14

in a sense, there are only two boys, an inside boy and an outside boy, and where those two boys are together (at around 8 o'clock) you actually don't see 100% of either of them, yet you count it as two boys in the A position, look at around 8 oclock where the two boys next to each other. look at the "inside" boy, and then move clockwise and you just see just his foot on the inside, continue and you see a leg, going a…

Yeah, I don't understand why moving the two boys side-by-side is considered a trick. It's much harder to understand how to be misled than to discover the solution.

Re: Disappearing Bicyclist – Sam Loyd (1906)

#37
post #13

Anybody want to figure out the year?

The puzzle was originally conceived in 1906. Love me some Sam Loyd, there is no greater chess puzzler in my mind.

It's the less-racist remix of his 1896 "Get Off The Earth" puzzle, which contains twelve or thirteen "chinamen" in the exact same poses around a globe.

http://www.marianotomatis.it/blog.php?post=blog/20110715&sec...

Whoever currently owns his name is still selling it, except now it refers to "warriors". https://www.samloyd.com/product/get-off-the-earth-card/

Re: Disappearing Bicyclist – Sam Loyd (1906)

#38

Is this just a visual version of the missing dollar riddle? https://en.wikipedia.org/wiki/Missing_dollar_riddle This was my grandpa's go to riddle for his grandkids (but with Francs). :-)

No... the missing dollar riddle asks people to confuse cash inflows and outflows by changing the subjective interpretation of a middleman, who starts out being an outflow (he/she is "part of the business") and then is treated like an inflow (he/she is "one of the money-havers"), it's essentially a linguistic puzzle in an accounting context, one person can be referred to in two different ways.

This one is closer to the missing square puzzle, https://en.wikipedia.org/wiki/Missing_square_puzzle .

This is a calculus puzzle, you have approximately 13 boys "missing a tiny slice" of themselves versus 12 boys with "an extra little slice" of themselves... it's more clever than just "we take the slices and reassemble them", it's "the slices slowly sweep across the boys' body so that when we slide the circles we essentially accumulate a whole 'second boy' inside the internal circle." Sort of like how the missing square puzzle has a clever way to have two almost-parallel lines which are not parallel hiding a long skinny rhombus containing the extra area, but the rearrangement exposes it in a much more visually arresting form as a whole missing square.

Re: Disappearing Bicyclist – Sam Loyd (1906)

#39

Earlier quoted context omitted.

The puzzle was originally conceived in 1906. Love me some Sam Loyd, there is no greater chess puzzler in my mind.

It's the less-racist remix of his 1896 "Get Off The Earth" puzzle, which contains twelve or thirteen "chinamen" in the exact same poses around a globe. http://www.marianotomatis.it/blog.php?post=blog/20110715&sec... Whoever currently owns his name is still selling it, except now it refers to "warriors". https://www.samloyd.com/product/get-off-the-earth-card/

Video demo of the "Get Off the Earth" which is a little jarring. It looks to be the same as a bike one. The video has lots of other versions/variations on these puzzles:

https://youtu.be/KdwJQbxLFHI?t=27

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