Hi DelDance,
It sounds like you're thinking of Promenade and Counter-Promenade Runs (fig 30 in Silver American Waltz). I think the videos are loading out of order, but click on the one that says "Natural - Pendular Sway" for the basic version.
Promenade and Counter-Promenade Runs are both an extension of Twinkles to Promenade and Counter-Promenade, which begin as a figure in Bronze (feet closing on each step 3) but which develop into the foot passing version in Silver. In the most basic version of Twinkles to PP & CPP, dancers are simply flip-flopping back and forth from promenade to counter promenade position, down line of dance in promenade and against line of dance in counter promenade (see fig 14).
That then develops into "Progressive" Twinkles to PP & CPP, where the couple moves down line of dance while the leader passes the follower in front of him, from his R side in PP to his left side in CPP. In the BallroomDancers.com syllabus, both of the progressive and non-progressive versions are part of figure #14, though one should really learn the non-progressive version first before working up to the progressive version.
Note that it's also possible for the leader to pass in front of the follower instead. The couple still moves down the line of dance, but turned around 180 degrees so that the leader and follower have effectively flipped positions. This one is much harder to lead and follow in a social dance setting, so it's really more of an academic exercise. But it's a very useful tool to prepare leaders for the next level.
A little later on in the silver level, this figure then develops into Promenade and Counter-Promenade Runs. This is where the above described inverted version of Progressive Twinkles to PP and CPP comes in handy, because it has taught the leader how to pass in front of the follower from one side to the other. With Promenade and Counter-Promenade Runs, they now take turns, leader passing in front first (PP to CPP), then follower on the next three steps (CPP to PP).
This too can be reversed, and that's how we get the left-turning or reverse version of PP & CPP Runs. Here the whole thing turns to the left, and the follower passes in front first (PP to CPP), followed by the leader (CPP to PP).
Put all of these things together and what you realize is that anybody can pass in front of anybody from PP to CPP or vice versa at any time, turning to the left or right. This of course is subject to the couple's ability to turn the appropriate amount based on their starting alignment in order to continue moving in the general direction of line of dance. To that end, reverses are more challenging because they require more rotation than do naturals, since the line of dance is counter clockwise.
Add to that the various arm and hand holds that can be used, plus the different sway shaping options (pendular, metronomic, etc), and you can get a ton of mileage out of just these two figures alone. Watch a couple dancing a silver level Waltz at a social dance, and you may find that up to half or more of their dance is comprised of some variation of these two figures alone.
Thanks for participating in the discussion! I hope I pointed you to the correct figures in the syllabus. Feel free to reply if you have further questions.
Regards,
Jonathan