Complex sentence: While a typical shape of a "teardrop" is straight-line tapering, they may be concave or "snowman": a secondary pad of smaller size is added at the junction overlapping with the primary pad (hence the nickname).
Split into simpler sentences: While a typical shape of a teardrop is straight-line tapering, they may be concave. To produce a "snowman"-shaped teardrop, a secondary pad of smaller size is added at the junction overlapping with the primary pad (hence the nickname).