Bowline Made from a Slip Knot

I prefer to make the bowline in this fashion. Note how the process starts with a bight, loop and bight.

The top bight is inserted into the loop.  This forms a slip knot.

 The remaining bight captures the loop formed by the slip knot.

 Once captured, the slip knot is pulled out.  Another way to say it is as follows: the slip knot is capsized (turned inside out).

Consider how a bowline was just formed by a slip knot.  Could it capsize the other direction?  Yes.  Thus the bowline alone isn't stable for the demands of climbing.  It needs to be backed up.

A common back-up is the Yosemite.  Here it is.