It is worth considering the objective of cast steel shot shape acceptance requirements. Shot peeners want the shot to be predominantly round (or at least roundish). They do not want to be supplied with grit. Hence the specifications divide shape into "Acceptable, Marginal and Unacceptable" categories. The diagrams of corresponding shapes are only illustrative - they are not comprehensive. Nodulation (caused by fusion during cooling) can involve one or more nodules. At one extreme there may be only one nodule, at the other there can be several. All are "Marginal". A very flat (pancake-shaped) particle is rare and is difficult to spot because it generally 'lies flat'. If the flatness is detected it would definitely be regarded as "elongated".
