Excellent response Tom.

By using a value of 0 for the third query within the LOC column, you're able to allow for multiple items to display on screen at once. A value of 1 will clear the screen.

~left word,"256,0,1",0,
~right word ,"768,0,0",500,

This syntax is interpreted by the software in the following manner:
1. Display the text, 'left word' at the location on your screen X: 256 , Y: 0 . Clear any stimuli still present before displaying this stimulus. Pause for 0 ms.
2. Display the text, 'right word' at the location on your screen X: 768 , Y: 0 . Keep displaying any stimuli still present. Pause for 500 ms.