Two features and both are practical. The flat barrel does not roll off a beam, a bench or a roof, which is the reason the shape exists. The wide rectangular lead marks rough sawn timber, brick and concrete where a round graphite core would break, and it can be sharpened to a chisel for a fine line or a broad one. Sharpen with a knife or a dedicated sharpener. See drawing pencils, sharpeners and site gear.
