Is it possible to change the size of the slide-box slides?

I’m trying to achieve the ability to see the edges (left and right side) of the other slides while viewing the current slide. I have a margin on the left and right of each slide to act as a divider between the slides, so that you can clear see that they are different slides. I would like to do this so that the user, can easily identify that other slides are available to be scrolled through. Any help would be great.