Yo-Yo Means to Go and Come Back again to where i started.
One single "YO" is the 1st Repetition, the YO-YO means 2 repetitions,
Like I goto the shops, and then i return from the shops.
1 round trip is a YO YO event, but in the repeats that is counted as 2, one for each YO.
Thus you can start with a small graphic, enlarge it and let it return to the same size, like a pulse. in a single widget. (Select YO-YO & Repeat 2)
HOVER implies a YO-YO but it is not a YO-YO, it is a programed return from where is now, to where it started on mouse exit.