On this early March afternoon, he was …

On this early March afternoon, he was participating in a routine one-on-one drill. The ball had swung around the perimeter and eventually would go to the ball-handler at the top of the key, who was allowed up to three dribbles to make a move. The defender — in this case, a sacrificial lamb named Garrison Mathews — would scurry inside the 3-point line, fundamentally closing out and hoping to deter a basket. “Hoping” is the operative word here. It was Wall’s turn to go. He received a pass and put the ball on the ground. One dribble, two steps and liftoff. He threw down a lefty slam glorious enough that its release today should quench any fans’ thirst for the sports world’s first new highlight in weeks.