def fheads
import bendtorch@1.3.0.0/main.bend as Bendtorchimport Base
2578def fheads(left: Nat, +hi: Nat, +dm: Dm, s: FS) -> FS:
2579 match left:
2580 case 0n:
2581 s
2582 case 1n+n:
2583 fheads(n, 1n+hi, dm, head_fwd(dm, head_cols(dm, hi), s))