I have seen many people who wind round enameled wire coils in the way they like. But I think if the number of turns overlaps one or more times, will any passing magnetic flux cancel out. In my opinion, winding one turn in the same direction (clockwise or counterclockwise) will make each turn of the coil generate equal electromotive force to appear efficient.

So, if you continue to wind the coil clockwise from one end to the other on the solid PVC pipe. Go back to the same end and wind it clockwise. Moving the bar magnet down through the PVC will generate an electromotive force. This winding structure does not result in the formation of two inductor coils. Both generate electromotive force in opposite directions, which cancel each other out.

All turns must be in the same direction, otherwise, you must cancel. Winding in the same direction, it must be wound in several layers to make full use of the coil. If you wind it like some kite strings, there will be a greater distance between the positions where the wires cross each other. Therefore, because the gap between the wires will increase, a high magnetic density will not be obtained.

And every turn of the copper magnet wire will increase the electromotive force. It is similar to a permanent magnet, in which each molecule of the magnet material increases the magnetic strength, even if placed side by side when most of the molecules are oriented in the same direction, the magnetic strength is stronger.