The method outlined below has been given the designation Suction Redwood. It is an extended variation of this concept used in Redwood, which is itself a variation of Kickback. Redwood is a method of continuing the auction if an immediate fit has been found in either of the Minor suits. Once interference has occurred with an overcall of No Trump, the responder has the opportunity to describe his holding further with the following bids as shown in the schematic.

Double:  This is for Penalty. Shows 15+ high card points. Partner must pass. 

2 Clubs: Shows Diamonds, or Spades and Hearts. 

2 Diamonds: Shows Hearts, or Spades and Clubs, both black suits. 

2 Hearts: Shows Spades, or Clubs and Diamonds, both Minors. 

2 Spades: Shows Clubs, or Diamonds and Hearts, both red suits. 

2 NT: Shows Pointed suits - Diamonds and Spades or Rounded suits - Clubs and Hearts. 

The use of the double gives the responder an added feature to show points instead of only distribution.