It was the after-lunch session, and the next batsman in hadn't left the bar. When it was his turn to bat he confessed to the captain that he could see three of everything.
'Well,' said the captain, 'when you get out to the wicket just hit the middle ball'
The batsman made his way to the middle and was bowled first ball.
'What happened?' asked the captain. 'Did you play the wrong ball?'
'No, the wrong bowler!'