+set comment {
+#
+Use of the screen:
+0 1 2 3 4 5 6 7
+xxxE hh hh hh hh hh hh hh hh hh hh hh hh hh hh hh hh_| abcd e_.. .... ...._|
+}
+# Display:
+# | is a vertical delimiter
+# E is either | to mean echo is on or ' to mean it is off
+# hh are hex digits of output:
+# 00-ff actual hex data (bold for stuff we entered)
+# 0-f under cursor: one digit entered, need the next
+# abcde_.... are ASCII output:
+# . things we can't print including SPC and _
+# in both, we may see
+# space we haven't yet filled
+# _ cursor when in other tab
+# xxx number of bytes read/written so far
+# Keystrokes:
+# TAB switch between hex and literal mode
+# ^C, ^D quit
+# ^Z suspend
+# Keystrokes in hex mode only:
+# RET move to a new line; if already at start of line,
+# set count to 0
+# DEL clear any entered hex digit
+# SPC send 00
+# ' toggle echo
+# nyi:
+# G-Z record last bytes we transmitted and store in memory
+# if we were halfway through a hex byte, first digit
+# is length of string to record
+# g-z play back memory