I read a short sci fy story when I was younger about the shape of time. It was determined that time was in a spiral and to time travel you had to move directly up or down the spiral. anyone familiar with this story. It may have been an old harlan ellison.
Larry Niven is one of my favorite writers...he writes and edits a lot of stories about time
Not sure if "A Hole in Space" was about spirals..."Playgrounds of the Mind" might have contained a short story about that...let us know if you remember is...I like fun fiction that challenges our imaginations...
Maybe: Spiral by Sarah Stasik
It sounds pretty sexy and starts out:
Nadia woke in the time spiral.
"Time is only a line, a curve, a wave of the hand, and its course is moved," said the man with the silver finger. But that was years ago, eons ago, minutes ago. She no longer knew.
Warm arms wrapped suddenly around her, and a husky voice whispered in her ear. "Not to be dramatic, but I think I must love you."
She didn't have to hold back tears anymore. She was prepared for the words. He slid from the bed with a groan. "I'm sorry; I have to go to work."
"I know," she said, lifting herself up for the kiss. He scooped clothing from the floor. "Rick?"
"Yes?"
"I think I must love you, too."
She'd see him again, in the turn of the spiral. Two years, if she rode it straight down. But she wouldn't. She never completed this turn of the spiral, not after the first time around.
No, never came across that one. Are you aware that there is a cult that thinks that time is a circle, every 5000 years the same things happen. We get reborn into the same person, so in 5000 years according to them I will be writing this to you. They are called the Brahma Kumari and are in most countries in the world.