Utthita Parsvakonasana (Extended Side Flank Pose) is another foundational standing pose.
Why are we using a block here? That's right! To open the chest.
See the post on Urdhva Hastasana to work on the movements of the top arm
Oh the places you can go from here! (hint: Parsva Janu Sirsasana) and the places you have come from (hint: Vrksasana)