Special metronome marks

[Carsten Steger]

I'm trying to create a metronome mark in LilyPond like the one in the
attached file, which indicates that two eighth notes should be
interpreted as eighth note triplets, but have failed so far. I am
aware from sections 1.6.3 and 1.8.2 of the Notation Reference Manual
that single notes can in principle be placed into a \markup command.
However, I have been unable to find out how I can create two barred
eighth notes or the triplet notation with \note commands in a \markup
command.  Any suggestions will be much appreciated.

Best regards, Carsten Steger

metronome-triplets.jpg
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