i had the G set as an alternate strafe left on two of my characters, the G is the alternate strafe rigth on two others.

the J is an alternate move forward on two, and an alternate move back on two and (GJ) gets me a simple box.

I assume to get a line I might have G as left/right on 2/2 characters and the J could be move left/right on only 1/1 of the characters. ( GJ gives a line )