M0x0 is an empty signbox in the middle lane. You found a conversion
In SignPuddle 1.5, the SignSpelling Sequence for diaper used 2
detailed location symbols.
In SignPuddle 1.6, the detailed location symbols have been dropped.
Across all of the various puddles, there appears to be a couple
dozen such problems. I'll investigate this further and fix the
errors first thing next week.
Thanks for the QA work,