Input (grade 11): Its 18 rounds are arranged as a source-heavy Feistel network, with 16 rounds of one type (MIXING) punctuated by two rounds of another type (MASHING).
Output (grade 12): Rounds are arranged as a source-heavy feistel network, with 16 rounds of one type called "mixing rounds" interleaved by two rounds of another type called "mashing rounds".