$('#slideshow .arrow').click(function(){
            var li            = slides.eq(current),
                canvas        = li.find('canvas'),
                nextIndex    = 0;

            // Depending on whether this is the next or previous
            // arrow, calculate the index of the next slide accordingly.

            if($(this).hasClass('next')){
                nextIndex = current >= slides.length-1 ? 0 : current+1;
            }
            if($(this).hasClass('previous')){
                nextIndex = current <= 0 ? slides.length-1 : current-1;
            }