There are three major approaches:
There's Pathfinder's blamgate approach:
http://www.hypergridbusiness.c...
And my watery things, which you can put inside any frame you like: http://virtualchristine.com/wp...
And the standard hypergate from The Hypergates network.
http://www.hypergridbusiness.c...
(Here next to a custom gate by Oliveira.)