This is the "smallest" possible valid Bongard Problem on black and white bitmap images (up to switching sides).
Adjacent-numbered pages: BP854 BP855 BP856 BP857 BP858  *  BP860 BP861 BP862 BP863 BP864
minimal, blackwhite, perfect, pixelperfect, experimental, funny, unstableworld
black_or_white_pixel [smaller | same | bigger]zoom in left (black_pixel) | zoom in right (white_pixel)
Aaron David Fairbanks
Adjacent-numbered pages: BP937 BP938 BP939 BP940 BP941  *  BP943 BP944 BP945 BP946 BP947
precise, stretch, boundingbox, invalid, experimental, preciseworld
rectangular_arrangement_of_white_pixels [smaller | same | bigger]zoom in left (square_arrangement_of_white_pixels) | zoom in right (oblong_rectangular_arrangement_of_white_pixels)
Leo Crabbe