Pictographic: step

bù,is comprised of two feet. In the oracle bones, the upper part is a left foot with the toe pointing upwords and the lower part is a right foot with the big toe also pointing.
But in the another direction. Two feet moving forwards one after another one after amoche graphics “walking forwards”. Which is the original meaning of bù “ steep”. It is also used as a nouns, and as an old unit of measurement. The modern version ofbù will keeps “the foot” in the upper part, but the lower part of it has been changed completely into another form.