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BP1 Empty image vs. non-empty image.
(edit; present; nest [left/right]; search; history)
COMMENTS

The first Bongard Problem.

All examples in this Bongard Problem are line drawings (one or more connected figures made up of curved and non-curved lines).

REFERENCE

M. M. Bongard, Pattern Recognition, Spartan Books, 1970, p. 214.

CROSSREFS

Adjacent-numbered pages:
  *  BP2 BP3 BP4 BP5 BP6

EXAMPLE

A circle fits on the right because it is not nothing.

KEYWORD

easy, nice, precise, allsorted, unstable, world, left-narrow, left-finite, left-full, left-null, perfect, pixelperfect, finished, traditional, stableworld, deformstable, bongard

CONCEPT empty (info | search),
existence (info | search),
zero (info | search)

WORLD

zoom in left (blank_image) | zoom in right (curves_drawing)

AUTHOR

Mikhail M. Bongard

BP4 Convex vs. concave.
(edit; present; nest [left/right]; search; history)
COMMENTS

All examples in this Problem are outlines of shapes or solid black shapes.

REFERENCE

M. M. Bongard, Pattern Recognition, Spartan Books, 1970, p. 215.

CROSSREFS

BP136 is the same solution (flipped) but with only polygonal outlines and also with extraneous dots distracting from the solution.

Adjacent-numbered pages:
BP1 BP2 BP3  *  BP5 BP6 BP7 BP8 BP9

KEYWORD

easy, nice, precise, unstable, right-narrow, finished, traditional, bongard

CONCEPT concave_convex_angle (info | search)

WORLD

outline_or_fill_shape [smaller | same | bigger]

AUTHOR

Mikhail M. Bongard

BP15 Closed shape outline vs. non-closed curve.
(edit; present; nest [left/right]; search; history)
COMMENTS

All examples in this Bongard Problem are non-self-intersecting curves.

REFERENCE

M. M. Bongard, Pattern Recognition, Spartan Books, 1970, p. 218.

CROSSREFS

Adjacent-numbered pages:
BP10 BP11 BP12 BP13 BP14  *  BP16 BP17 BP18 BP19 BP20

KEYWORD

nice, unstable, world, finished, traditional, bongard

CONCEPT closed_open (info | search),
hole (info | search),
loop (info | search)

WORLD

curve_or_outline [smaller | same | bigger]
zoom in left (shape_outline) | zoom in right (curve)

AUTHOR

Mikhail M. Bongard

BP72 Ends of the curve are parallel vs. ends of the curve are perpendicular.
(edit; present; nest [left/right]; search; history)
REFERENCE

M. M. Bongard, Pattern Recognition, Spartan Books, 1970, p. 237.

CROSSREFS

Adjacent-numbered pages:
BP67 BP68 BP69 BP70 BP71  *  BP73 BP74 BP75 BP76 BP77

KEYWORD

nice, precise, unstable, ignoreimperfections, finished, traditional, bongard

CONCEPT slope_at_endpoint (info | search),
tracing_line_or_curve (info | search),
parallel (info | search),
perpendicular (info | search)

WORLD

curve [smaller | same | bigger]

AUTHOR

Mikhail M. Bongard

BP211 More black than white vs. more white than black.
(edit; present; nest [left/right]; search; history)
CROSSREFS

See BP196 for a version of this Problem restricted to uniform textures.

Adjacent-numbered pages:
BP206 BP207 BP208 BP209 BP210  *  BP212 BP213 BP214 BP215 BP216

KEYWORD

easy, nice, spectrum, dual, blackwhite, unstable, right-null, perfect, pixelperfect, traditional, continuous, viceversa, bordercontent

CONCEPT outlined_filled (info | search),
size (info | search),
texture (info | search)

WORLD

bmp [smaller | same | bigger]
zoom in left | zoom in right

AUTHOR

Giuseppe Insana

BP324 Left shapes can be placed on top of each other to make right shape vs. not so.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP319 BP320 BP321 BP322 BP323  *  BP325 BP326 BP327 BP328 BP329

KEYWORD

precise, unstable, perfect, pixelperfect, structure, orderedtriplet, traditional

CONCEPT set_union (info | search),
same_shape (info | search),
same (info | search)

AUTHOR

Aaron David Fairbanks

BP325 Left shapes can combine by symmetric difference (XOR logical operator) to make right shape vs. left shapes can combine by intersection (AND logical operator) to make right shape.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP320 BP321 BP322 BP323 BP324  *  BP326 BP327 BP328 BP329 BP330

KEYWORD

precise, unstable, perfect, pixelperfect, structure, orderedtriplet, traditional

CONCEPT xor (info | search),
overlap (info | search)

AUTHOR

Aaron David Fairbanks

BP335 Tessellates the plane vs. does not tessellate the plane.
(edit; present; nest [left/right]; search; history)
COMMENTS

EX7152 is an example of a shape than can be stretched in such a way that it no longer tessellates the plane. This is a property that is only exhibited by shapes that tessellate with rotated copies of themselves. - Leo Crabbe, Mar 05 2021

CROSSREFS

Adjacent-numbered pages:
BP330 BP331 BP332 BP333 BP334  *  BP336 BP337 BP338 BP339 BP340

KEYWORD

nice, stretch, unstable, math, hardsort, creativeexamples, proofsrequired, perfect, pixelperfect, traditional

CONCEPT infinite_plane (info | search),
tessellation (info | search),
tiling (info | search)

WORLD

shape [smaller | same | bigger]
zoom in left (fill_shape)

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

BP348 Shape on the right is the convex hull of shape on the left vs. not so.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP343 BP344 BP345 BP346 BP347  *  BP349 BP350 BP351 BP352 BP353

KEYWORD

nice, precise, unstable, perfect, orderedpair, traditional

CONCEPT convex_hull (info | search)

WORLD

2_fill_shapes [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

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