digraph {
        /* new idea */

        {rank=same; M_entry_whole_code M_title M_entry_allocation M_entry_interactive}
        M_entry_whole_code [label="whole\ncode"]
        M_entry_whole_code -> M_S1
        M_title [label="Message\nMachine" style="dotted"]
        M_entry_whole_code -> M_title [style="invis"]
        M_entry_allocation [label="allocation"]
        M_entry_allocation -> M_S1B [label="already\nconnected"]
        M_entry_interactive [label="interactive"]
        M_entry_interactive -> M_S1B

        {rank=same; M_S1 M_S1B}
        M_S1 [label="1: know nothing"]
        M_S1B [label="1: know nothing\n(bound)"]
        M_S1 -> M_S1B [label="connect()"]
        M_S1B -> M_S1 [label="lose()"]

        M_S1 -> M_S2 [label="M_set_nameplate()"]
        M_S1B -> M_P_claim1 [label="M_set_nameplate()"]
        M_P_claim1 [shape="box" label="tx claim()"]
        M_P_claim1 -> M_S2B

        {rank=same; M_S2 M_S2B M_P_claim2}
        M_S2 [label="2: know nameplate\nwant claim\nunknown mailbox\nwant open"]
        M_S2B [label="2: know nameplate\nwant claim\nunknown mailbox\nwant open\n(bound)"]
        M_S2 -> M_P_claim2 [label="connect()"]
        M_S2B -> M_S2 [label="lose()"]
        M_P_claim2 [shape="box" label="tx claim()"]
        M_P_claim2 -> M_S2B
        M_S2 -> M_P2_queue [label="M_send(msg)" style="dotted"]
        M_P2_queue [shape="box" label="queue" style="dotted"]
        M_P2_queue -> M_S2 [style="dotted"]
        M_S2B -> M_P2B_queue [label="M_send(msg)" style="dotted"]
        M_P2B_queue [shape="box" label="queue" style="dotted"]
        M_P2B_queue -> M_S2B [style="dotted"]

        M_S2 -> M_S3 [label="(none)" style="invis"]
        M_S2B -> M_P_open [label="rx_claimed()"]
        M_P_open [shape="box" label="store mailbox\ntx open()\ntx add(queued)"]
        M_P_open -> M_S3B

        {rank=same; M_S3 M_S3B M_P3_open M_P3_send}
        M_S3 [label="3: claimed\nknown mailbox\nwant open"]
        M_S3B [label="3: claimed\nknown mailbox\nwant open\n(bound)"]
        M_S3 -> M_P3_open [label="connect()"]
        M_S3B -> M_S3 [label="lose()"]
        /*M_S3B -> M_S2 [label="lose()"]*/ /* not worth it */
        M_P3_open [shape="box" label="tx open()\ntx add(queued)"]
        M_P3_open -> M_S3B
        M_S3B -> M_S3B [label="rx_claimed()"]
        M_S3B -> M_P3_send [label="M_send(msg)"]
        M_P3_send [shape="box" label="queue\ntx add(msg)"]
        M_P3_send -> M_S3B
        M_S3 -> M_P3_queue [label="M_send(msg)" style="dotted"]
        M_P3_queue [shape="box" label="queue" style="dotted"]
        M_P3_queue -> M_S3 [style="dotted"]

        M_S3 -> M_S4 [label="(none)" style="invis"]
        M_S3B -> M_P3_process_ours [label="rx_message(side=me)"]
        M_P3_process_ours [shape="box" label="dequeue"]
        M_P3_process_ours -> M_S3B
        M_S3B -> M_P3_process_theirs [label="rx_message(side!=me)"]
        M_P3_process_theirs [shape="box" label="tx release()\nprocess message"]
        M_P3_process_theirs -> M_S4B
        M_S3B -> M_P3_close [label="M_close()"]
        M_P3_close [shape="box" label="tx release()\n"]
        M_P3_close -> M_P_close

        {rank=same; M_S4 M_P4_release M_S4B M_P4_process M_P4_send M_P4_queue}
        M_S4 [label="4: released\nunwant nameplate\nwant mailbox\nopen\n"]

        M_S4B [label="4: released\nunwant nameplate\nwant mailbox\nopen\n(bound)"]
        M_S4 -> M_P4_release [label="connect()"]
        /* it is currently an error to release a nameplate you aren't
        currently claiming, so release() is not idempotent. #118 fixes that */
        M_P4_release [shape="box" label="tx open()\ntx add(queued)\ntx release()"]
        /*M_S4B -> M_S4B [label="rx_claimed() *#118"]*/
        M_S4B -> M_P_close [label="M_close()"]
        M_S4B -> M_P4_send [label="M_send(msg)"]
        M_P4_send [shape="box" label="queue\ntx add(msg)"]
        M_P4_send -> M_S4B
        M_S4 -> M_P4_queue [label="M_send(msg)" style="dotted"]
        M_P4_queue [shape="box" label="queue" style="dotted"]
        M_P4_queue -> M_S4 [style="dotted"]

        M_P4_release -> M_S4B
        M_S4B -> M_S4 [label="lose()"]
        /*M_S4B -> M_S2 [label="lose()"]*/
        M_S4B -> M_P4_process [label="rx_message()"]
        M_P4_process [shape="box" label="process message"]
        M_P4_process -> M_S4B

        M_S4 -> M_S5 [label="(none)" style="invis"]
        M_S4B -> M_S5B [label="rx_released()"]

        seed [label="from Seed?"]
        seed -> M_S5
        {rank=same; seed M_S5 M_S5B M_P5_open M_P5_process}
        M_S5 [label="5: released\nunwant nameplate\nwant mailbox\nopen\n"]
        M_S5B [label="5: released\nunwant nameplate\nwant mailbox\nopen\n(bound)" color="green"]
        M_S5 -> M_P5_open [label="connect()"]
        M_P5_open [shape="box" label="tx open()\ntx add(queued)"]
        M_P5_open -> M_S5B
        M_S5B -> M_S5 [label="lose()"]
        M_S5B -> M_P5_process [label="rx_message()"]
        M_P5_process [shape="box" label="process message"]
        M_P5_process -> M_S5B
        M_S5B -> M_P5_send [label="M_send(msg)"]
        M_P5_send [shape="box" label="queue\ntx add(msg)"]
        M_P5_send -> M_S5B
        M_S5 -> M_P5_queue [label="M_send(msg)" style="dotted"]
        M_P5_queue [shape="box" label="queue" style="dotted"]
        M_P5_queue -> M_S5 [style="dotted"]

        M_S5 -> M_S6 [label="M_close()"]
        /*M_S5 -> M_P7_drop [label="M_close()"]*/
        M_S5B -> M_P_close [label="M_close()"]
        M_P_close [shape="box" label="tx close()"]
        M_P_close -> M_S6B

        {rank=same; M_S6 M_P6_close M_S6B}
        M_S6 [label="6: closing\nunwant mailbox\nopen\n"]
        M_S6B [label="6: closing\nunwant mailbox\nopen\n(bound)"]
        M_S6 -> M_P6_close [label="connect()"]
        M_P6_close [shape="box" label="tx close()"]
        M_P6_close -> M_S6B
        M_S6B -> M_S6 [label="lose()"]
        M_S6B -> M_S6B [label="rx_released()"]
        M_S6B -> M_S6B [label="M_close()"]
        M_S6B -> M_S6B [label="M_send()"]
        M_S6 -> M_S6 [label="M_send()"]

        M_S6 -> M_S7 [label="(none)" style="invis"]
        /*M_S6 -> M_P7_drop [label="M_close()"]*/
        M_S6B -> M_P7_drop [label="rx_closed()"]
        M_P7_drop [shape="box" label="C_stop()"]
        M_P7_drop -> M_S7B

        {rank=same; M_S7 M_S7B}
        M_S7 [label="7: closed\n"]
        M_S7B [label="7: closed\n(bound)"]
        M_S7 -> M_S7B [label="connect()" style="invis"]
        M_S7B -> M_S7 [label="lose()"]
        M_S7B -> M_S7B [label="M_close()"]
        M_S7B -> M_S7B [label="M_send()"]


        M_process [shape="box" label="process"]
        M_process_me [shape="box" label="dequeue"]
        M_process -> M_process_me [label="side == me"]
        M_process_them [shape="box" label="" style="dotted"]
        M_process -> M_process_them [label="side != me"]
        M_process_them -> M_process_pake [label="phase == pake"]
        M_process_pake [shape="box" label="WM_rx_pake()"]
        M_process_them -> M_process_other [label="phase in (version,numbered)"]
        M_process_other [shape="box" label="WM_rx_msg()"]

}