To get into the "Reverse Becket" formation, start in duple improper formation. Then the ladies trade places, and everyone is next to their partner but backwards from normal Becket formation.

The A1 is easy to do but hard to describe! After "balance the ring" partners are holding hands, gent's left in lady's right. "Nevada twirl" is just a "California twirl" with these opposite hands -- partners raise joined hands and trade places, with the lady ducking under the arch. (As partners pass, gents are to the inside of the set and ladies outside.) Then face partner without letting go of hands, and reach across the set to join free hand with neighbor and form a "cloverleaf". After balancing in this formation, an easy California twirl with neighbor re-forms the original ring (rotated 1/2).

The progression in B2 is satisfying, but dancers will be late unless helped out by attention to timing during the walk-through and precise (early?) calls during the dance. Take just two steps to cross the set, turning right immediately after passing neighbor to face single file up or down the set. Then two more steps to meet the next couple, and four steps to circle halfway.

As to the title "Retronella" -- the dance is loosely similar in structure to Petronella, but is "retro" (backwards) in numerous respects: the reverse Becket formation, progressing on the other side of the set, ladies leading the progression (scandalous...), and gents moving around the ring in the opposite direction as Petronella. And one more -- when waiting out at the ends, dancers should stay as they are, resisting the urge to cross over. Despite all this retrocity I have found the dance to be popular and not disorienting.