Linear easing on scale with playback_loop_forward [maths questions]]

I’m creating a tunnel effect where a GO is zoomed in on a loop to create a psychedelic never-ending tunnel effect.

It’s working okay so far with this animate function

	gui.animate(node, "scale", 1.5, gui.EASING_LINEAR, 0.5, 0, nil, gui.PLAYBACK_LOOP_FORWARD)

But the problem (which is a little hard to explain) is that there’s a noticeable jerk each time the loop restarts. It’s because scaling involves multiplication. So the start of the loop appears a little faster. The difference is very noticeable if i make the animation time long.

I believe this can be counteracted by using a non-linear easing. But which easing would be right for this job?