Yeah, I think the story is that Penrose saw an illusion in an Escher print that encouraged him to create the Penrose Triangle, his dad Lionel created the Penros

Yeah, I think the story is that Penrose saw an illusion in an Escher print that encouraged him to create the Penrose Triangle, his dad Lionel created the Penrose staircase, and then sent a copy of these in the paper "Impossible objects..." to Escher, who then used the staircase in "Ascending and Descending" and others. It's kind of cool that they cite eachother in these works as inspiration here. I bet Escher could have made an interesting print of them pointing at one another in some kind of impossible object. And apparently neither Penrose nor Escher knew about Oscar Reutersvärd's work! Oscar got robbed lol.