Screen('DrawLine', windowPtr [,color], fromH, fromV, toH, toV [,penWidth]);
[wPtr, rect] = Screen('OpenWindow', 0)
Screen('DrawLine', wPtr, [180, 40, 80], 1000, 800, 1600, 1200, [10]);
Screen('Flip', wPtr);
[wPtr, rect] = Screen('OpenWindow', 0)
Screen('DrawLine', wPtr, [180, 40, 80], 1000, 800, 1600, 1200, 10);
Screen('Flip', wPtr);