From firstname.lastname@example.org Tue May 3 15:45:11 1994
Date: Mon, 2 May 1994 18:09:11 +0100 (BST)
Organisation: Dept of EEEng, Univ of Surrey, Guildford GU2 5XH, England
X-Mailer: ELM [version 2.4 PL20]
there is another implementation of the sequencer
S = en?;[in1? -> out1!;S  in2? -> out2!;S]
in the paper
the implementation there uses four asynchronous latches
which replace the toggles and the DW element in
the paper also discusses a compilation technique
based on a generalisation of the DW element.
here is another "unsafe" but practical and simpler implementation.
"unsafe" because the "clear off" process, which converts
two phases to four phases signalling, is concurrent with
forwarding the output.