- The wall at Smith–Ninth Streets has rough concrete, retaining scuff marks from commuters leaning against it.
- A darkened band about 18 inches above the floor is formed by aggregated shoe marks.
- Using a photo, the author isolated the scuff region, converted pixel coordinates to inches via a keypad reference.
- Relative luminance analysis showed darkness levels against height, indicating scuff frequency.
- Experimentally, a scuff mark was found to be about 27% up the body height, yielding a height-to-scuff ratio.
- Applying this ratio to the data estimated commuter heights, but variance was too wide due to inconsistent leg angles.
- Future work involves Bayesian correction using angle distributions and encourages collaboration on wear pattern studies.