The Dink Network

You can use the variables like that, however the 3rd bit in move() is the x or y coordinate to move to, not the amount of pixels to move. It's the y position if you're moving up or down and the x position for any other direction.
So if &strength is 5, that is trying to move the rock to 5 pixels from the left of the screen. If it's already further away than that (as is likely ) then it won't move at all.

Your 2nd idea is what you need to do but you can't stick it all together like that, seperate it out:

&location = sp_x(&current_sprite, -1);
&location += 5;
move(&current_sprite, 6, &location, 1);

Edit: Or if you're basing it on strength or something then you could also do this of course:

&location += &strength;