“You cannot step twice into the same river, for other waters are continually flowing on.”
“We can none of us step into the same river twice, but the river flows on and the other river we step into is cool and refreshing, too”
“The same river can never be crossed twice. The flowing water has no memory of footprints.”
“No one has ever stepped twice into the same river. But did anyone ever step twice into the same book?”
“No man ever steps in the same river twice, for it's not the same river and he's not the same man.”
“You never step in the same river of thought twice, because neither you nor it are the same.”