These are inspired by the symbol shapes in candlestick financial charts: "The bullish harami shows a downtrend of negative-colored (black) candlesticks engulfing a small positive (white) candlestick, giving a sign of a reversal of the downward trend." They also might suggest cigarettes or syringes if you didn't know the background. I see them as a "cell" as they are used in music, which are short thematic elements that are used as building blocks to generate the work.
One of the ideas I had initially was to do them in encaustic and/or crayon as clever self-reference (wax). Perhaps the next in the series ("Three Line Strike").
The titles of the charts were also very cool:
Three Line Strike