Shirt pockets.
In the original Star Trek series, Warp 1 was 7 times the speed of light. Warp 2, was 7 times Warp 1 or 49 times the speed of light. Warp 9 was really fast.
Roddenberry revised this with the Next Generation. I don't remember the numbers but at Warp 10, you were going so fast, you were everywhere at once.