This is METAFONT, Version 2.7 // 2.8cs (base=plain 93.7.31)  27 FEB 1995 16:42
**&plain \mode=proof; screenchars; input c:/metafont/inputs/lib/waits.mf
(c:/metafont/inputs/lib/waits.mf)
*23

*345
>> 23
! Isolated expression.
<to be read again> 
                   345
<*> 345
       
? 
! Extra tokens will be flushed.
<to be read again> 
                   345
<*> 345
       
? QUIT
OK, entering batchmode...
! Emergency stop.
<*> 345
       
*** (job aborted, no legal end found)