低三下四

• 亻(person; human; man)RADICAL
• 氐(low foundation; root base)PHONO-SEMANTIC

A person bending down to the roots is truly at the lowest point.

• 一(one; horizontal stroke)ASSOCIATIVE
• 二(two (pictograph – two horizontal strokes))ASSOCIATIVE

Three horizontal strokes stacked on top of each other symbolize the number three.

• 一(horizontal line; boundary)RADICAL
• 卜(stroke descending downward)ASSOCIATIVE

A vertical stroke pointing downward across a boundary line marks 'below'.

• 囗(frame; surround)RADICAL
• 儿(person; foot)ASSOCIATIVE

Four sides of a square frame surround two legs — the ancient form of the number four.