The meaning of "big" left intentionally vague. There are various specific ways to define size, such as diameter, minimum distance between points on edge, and size of smallest bounding circle.

All examples in this Bongard Problem are single simple shapes, either outlines or solid black.

All examples on the same side are approximately the same size.

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

Adjacent-numbered pages:
BP1  *  BP3 BP4 BP5 BP6 BP7

easy, nice, fuzzy, spectrum, size, stable, finished, traditional, continuous, bongard

outline_or_fill_shape [smaller | same | bigger]

Mikhail M. Bongard