I made a long list of movie names. It would display 20 names at a time.
I set it up to skip 10 lines at a time.

onRotary = function(clicks) {
if (clicks > 1) {
     // Skip 10 lines
     } ;
} ;

In my Chanel Blaster in Project Boredom 2  [Link: mediafire.com] , I did something different like . . .

if (clicks > .99) {
defaultchannel ++ ; // up one
} ;

if (clicks > 1) {
defaultchannel +=10 ; // up 10
} ;

if (clicks < -1) {
defaultchannel -- ; // down 1
} ;

It's not a algorithm , but it worked .