"He walks — he can’t lift his feet out of the grass, you know, it’s only two inches... and it looks like he’s walking on toothpicks."

Said Trump, observing our President's frailty, quoted in "Trump: ‘We Have A President Who Can’t Walk, Can’t Talk’" (The Federalist).

ADDED: The quote is from Trump's interview with Tucker Carlson. Here's the transcript, where you can see he goes on at some length about Biden's difficulty walking — not just on grass, but on sand — and expatiates about the symbolism of "the beach":

Well, I think he’s worse mentally than he is physically. And physically, he’s not exactly a triathlete, or any kind of an athlete. You look at him, he can’t walk to the helicopter. He walks. He can’t lift his feet out of the grass. It’s only two inches at the White House, right? It’s not a lot. But you watch him and it looks like he’s walking on toothpicks. And then you see him in the beach where he can’t lift a chair. You know those chairs are meant to be light, right? They’re like, two ounces. You lift them up. He can’t lift the chair. He can’t walk to the chair. 

And I don’t know what they’re doing with the beach. This beach is seeming to play a big role. But they love pictures of him on the beach. I think he looks terrible on the beach. He looks terrible on the beach.... Well, he can’t walk through the sand. You know, sand is not that easy to walk through. But when he walks through it, he can’t walk through the sand. And there’s somebody in there that thinks he looks fabulous at the beach. I think he looks horrible at the beach. 

Plus, the beach doesn’t represent what a president’s supposed to be doing. He’s supposed to be working, he’s supposed to be getting us out of that horrible, horrible war that we’re very much involved in with Russia and Ukraine. You could do that. You could do that very easily. I believe you could do that very… I don’t believe he could do it because he’s just incompetent....