.VERBON 2
code block on the first line
.VERBOFF
.P
Regular text.
.VERBON 2
code block indented by spaces
.VERBOFF
.P
Regular text.
.VERBON 2
the lines in this block  
all contain trailing spaces  
.VERBOFF
.P
Regular Text.
.VERBON 2
code block on the last line
.VERBOFF