that doesn't seem right, Paul. The pieces in Triazzle are triangular, not "frog-shaped".
I did have a puzzle (maybe still do) in which all the pieces were lizards.
Something like that? About 18"x18"?
That sounds like the right size and they could very well have been lizard shapes rather than frogs. It was a pretty abstract representation of an animal and I wasn't very old.
Had a look at Triazzle that isn't the one. Thanks though for the suggestion.