Diaslen (also denoted 4s in groundfault's aberrismic theory) is a family of quasi-diatonic ternary scale patterns with scale signature 5L2m4s, so named by groundfault who considers 33edo's L:m:s = 5:2:1 a good tuning for it. The name diamech is a blend of dia- and the TAMNAMS prefix mech- for machinoid.

The three canonical diamech scale patterns, denoted 4sL, 4sC, and 4sR, may be constructed via MOS substitution, giving generator sequences for the three scales:

5L2m4s as MOS_subst(5, 2, 4; m, s; k)
k filling MOS UDP for filling MOS step pattern generator sequence MOS for s = 0
template MOS: LXLXLXLXLXX intvl. class of gen.:(*) 2-steps
2 (4sC) mssmss 4|0(2) LmLsLsLmLss GS(L+m, L+s, L+s) yes
1 (4sR) smssms 2|2(2) LsLmLsLsLms GS(L+s, L+m, L+s) yes
0 (4sL) ssmssm 0|4(2) LsLsLmLsLsm GS(L+s, L+s, L+m) yes