OpenBSD-4.6/usr.bin/learn/lib/eqn/L4.2a

#once #create message
.ND
.LP
Another practice one for using "over".
Modify the file "Example" so it produces
output that looks like this one, then type "ready".
.pl 1
#once #create Ref
.LP
.EQ
a + b over c + d = e over f
.EN
.pl 1
#once #create Example
.LP
.EQ
replace me
.EN
.pl 1
#
#once neqn Ref | nroff >X1 &
#once neqn message Ref | nroff -T$term %s/tinyms -
#user
neqn Example | nroff >X2
#cmp X1 X2
#log
#next
4.1b 10