The 人-shaped cap on top serves as the indexing radical. Originally 余 depicted a thatched shed or shelter; the roof-like apex was reanalyzed as the 人 (person) radical, grouping 余 with other person-radical entries in traditional Kangxi lookup.
pictograph
余yú
surplus; remainder; I (literary)
The lower portion shows the body of the original shelter-pictograph with vertical post and crossing beams. It does not split into independent named pieces, so it is shown as the residual silhouette that combines with the 人 cap to form the complete sheltered-figure graph.
