I traded E-mails with Mark for three different decades and got
to visit him several times in the 90's whenever I was passing through
Seattle. Hop on the ferry, have deep political discussions with him
(although I never exactly agreed with him he was always willing to
discuss!) at the diner, and play with KS-10's, TU-77's, and Massbus disks.
Rest in peace, Mark.
Tim.