Talk:Canal surface

"On the contrary, if a regular curve..." — I suspect, "vice versa" is meant (or "conversely") rather than "on the contrary"; but being not a native English speaker I am not sure. By the way, the corresponding article in Russian does not contain this part. Boris Tsirelson (talk) 20:38, 17 November 2017 (CET)

I would have written "conversely", or, less formally, "on the other hand" or "in the opposite direction". Richard Pinch (talk) 22:30, 17 November 2017 (CET)

Nice; I did. Boris Tsirelson (talk) 23:29, 17 November 2017 (CET)