Germany in the 70s. We had no private television back then, only two nation wide stations and one station per state. The nation wide stations had cartoon interstitials but the Bavarian one still had Lissajous in the 70s.

I found this Youtube video [1] from the mid 80s as an example. The comments say (auto-translated):

"There was a big report in the Elrad 06/1997 about the advertising separators and an interview with the man who produced them. Filmed from an oscilloscope, copied to positive film, coloured and mixed with other figures. Everything was produced analogue, partly with bicycle dynamos and tape heads with a circular saw blade between the magnet and the pick-up, quite interesting to read what kind of effort was put into it..."

And off-topic but funny if true:

"By the way, the blondie in the Duplo ad is Jason Connery, Sean's son. He probably also played Robin Hood in the English series at about the same time."

[1] https://m.youtube.com/watch?v=15WqxmKZbTc&t=189s

EDIT: One of the nation wide stations had cartoons, the other I don't remember.

Not an interstitial (and am not the original poster), but, somewhat related, ABC (the Australian Broadcasting Corporation)'s logo is a Lissajous curve:

https://en.wikipedia.org/wiki/Australian_Broadcasting_Corpor...

The article does mention that 'In the early years of television, the ABC had been using Lissajous curves as fillers between programmes.'