Here is a related link
yma16
2009-11-29 13:30:03
( reads)
http://web.wenxuecity.com/BBSView_archives.php?SubID=netiq&MsgID=118341&yr=2007
The link says it should have a limit. I estimated it for a few steps, it seems it >2. I think you need many more steps if you want it be close to 4.