Sink vent in an island

[Fred Robertson]

A few weeks ago i posted a question to you about how to configure a drain and vent plumbing for a sink in a island in the middle of the kitchen. I'm looking to understand the "loopback techique". You emailed back and said you would get back to me with some sketches or drawings, but it's now been 2-3 weeks so I thought I would re-ask the question. Please advise. thanks Fred