The use of an opening two-level bid in diamonds, hearts or spades as a one- round force to show a strong hand, normally with at least eight playing tricks, which is not strong enough or unsuitable for an Acol 2♣ opening. The bid promises either a six-card suit or two good five-carders.
With the first hand, you open 2♠ expecting to rebid 3♠ over a 2NT negative response. With the second hand, you open 2♥ and plan to rebid 3♦.
Many authorities regard it as inefficient to allocate three opening bids to these near game hands and Acol Two bids are going out of fashion.