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BP341 Strictly increasing or strictly decreasing border line vs. both increasing and decreasing border line.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP336 BP337 BP338 BP339 BP340  *  BP342 BP343 BP344 BP345 BP346

KEYWORD

math, perfect, pixelperfect, traditional

CONCEPT size_increase_decrease (info | search),
or (info | search),
outlined_filled (info | search),
tracing_line_or_curve (info | search),
texture (info | search)

WORLD

function_graph_black_below_white_above [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

BP344 Shape can tile itself vs. shape cannot tile itself.
(edit; present; nest [left/right]; search; history)
COMMENTS

Left examples are sometimes called "rep-tiles."


The tiles all must be the same size. More specifically, all left examples can tile themselves only using scaled down and rotated versions of themselves with all tiles the same size. Right examples cannot tile themselves using scaled down rotated versions of themselves or even reflected versions of themselves with all tiles the same size.


Without the puzzle piece-like shape EX4120 on the right side the current examples also allow the solution "shape can tile with itself so as to create a parallelogram vs. shape cannot tile with itself so as to create a parallelogram."

CROSSREFS

See BP532 for a version with fractals.

Adjacent-numbered pages:
BP339 BP340 BP341 BP342 BP343  *  BP345 BP346 BP347 BP348 BP349

EXAMPLE

Go to https://oebp.org/files/yet.png for an illustration of how some left-sorted shapes tile themselves.

KEYWORD

hard, nice, precise, notso, unstable, math, hardsort, creativeexamples, proofsrequired, perfect, traditional

CONCEPT recursion (info | search),
self-reference (info | search),
tiling (info | search),
imagined_shape (info | search),
imagined_entity (info | search)

WORLD

shape [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

BP369 All points (small white circles) on one figure can be glued together to make the other figure vs. not so.
(edit; present; nest [left/right]; search; history)
CROSSREFS

See BP851 for a version where the figure must stay within the 2D plane and cannot pass through itself while being deformed.

Adjacent-numbered pages:
BP364 BP365 BP366 BP367 BP368  *  BP370 BP371 BP372 BP373 BP374

KEYWORD

nice, math, traditional

CONCEPT topological_transformation (info | search),
imagined_motion (info | search),
motion (info | search)

WORLD

zoom in left (figure_made_of_curves_and_quotient_by_hollow_dots)

AUTHOR

Aaron David Fairbanks

BP370 Gluing sides with the same symbols makes a sphere vs. gluing sides with the same symbols makes a torus.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP365 BP366 BP367 BP368 BP369  *  BP371 BP372 BP373 BP374 BP375

KEYWORD

math

CONCEPT topological_transformation (info | search),
3d_solid (info | search),
imagined_motion (info | search),
motion (info | search)

AUTHOR

Aaron David Fairbanks

BP378 The two objects are conceptually related vs. the two objects are conceptually unrelated.
(edit; present; nest [left/right]; search; history)
CROSSREFS

See BP347, which is similar.

Adjacent-numbered pages:
BP373 BP374 BP375 BP376 BP377  *  BP379 BP380 BP381 BP382 BP383

KEYWORD

abstract, math, unorderedpair, traditional

CONCEPT same_concept (info | search),
same (info | search)

AUTHOR

Aaron David Fairbanks

BP380 The completed version of the collection indicated by the objects is finite vs. the completed version of the collection indicated by the objects is infinite.
(edit; present; nest [left/right]; search; history)
COMMENTS

Related to BP870 and BP792.

CROSSREFS

Adjacent-numbered pages:
BP375 BP376 BP377 BP378 BP379  *  BP381 BP382 BP383 BP384 BP385

KEYWORD

nice, math, creativeexamples, traditional, rules

CONCEPT finite_infinite (info | search)

AUTHOR

Aaron David Fairbanks

BP381 Adding the top two waves yields the bottom wave vs. not so.
(edit; present; nest [left/right]; search; history)
COMMENTS

This problem is about wave interference.

CROSSREFS

Adjacent-numbered pages:
BP376 BP377 BP378 BP379 BP380  *  BP382 BP383 BP384 BP385 BP386

KEYWORD

nice, notso, math, orderedtriplet, traditional

CONCEPT addition (info | search),
wave (info | search),
2_inputs_1_output (info | search)

AUTHOR

Aaron David Fairbanks

BP382 No knot (unknot) vs. knot.
(edit; present; nest [left/right]; search; history)
COMMENTS

To hint at the solution, left examples can be arranged in a sequence to show the unknot tying itself.

CROSSREFS

Adjacent-numbered pages:
BP377 BP378 BP379 BP380 BP381  *  BP383 BP384 BP385 BP386 BP387

KEYWORD

nice, math, anticomputer, help, traditional

CONCEPT knot (info | search),
topological_transformation (info | search)

WORLD

knot [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

BP384 Square number of dots vs. non-square number of dots.
(edit; present; nest [left/right]; search; history)
COMMENTS

All examples in this Problem are a collection of dots.


An equivalent solution is "Dots can be arranged into a square lattice whose convex hull is a square vs. not so". - Leo Crabbe, Aug 01 2020

CROSSREFS

Adjacent-numbered pages:
BP379 BP380 BP381 BP382 BP383  *  BP385 BP386 BP387 BP388 BP389

EXAMPLE

A single dot fits because 1 = 1*1.

A pair of dots does not fit because there is no integer x such that 2 = x*x.

KEYWORD

nice, precise, allsorted, number, math, left-narrow, left-null, help, traditional, preciseworld

CONCEPT square_number (info | search)

WORLD

dots [smaller | same | bigger]

AUTHOR

Jago Collins

BP505 Number indicated on number line conceptually related to image shown below vs. not so.
(edit; present; nest [left/right]; search; history)
COMMENTS

This is the "easier version" of BP801.


All numbers on the left are canonical mathematical constants, i.e. there are no totally arbitrary ratios, with images below featuring those ratios.

CROSSREFS

Adjacent-numbered pages:
BP500 BP501 BP502 BP503 BP504  *  BP506 BP507 BP508 BP509 BP510

KEYWORD

fuzzy, math

CONCEPT number (info | search),
ratio (info | search)

AUTHOR

Aaron David Fairbanks

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