Gradient colour transition

Hi Sylvia,

Please excuse the hurriedly drawn pipework and motion path, but I thought this example might give you something to work with. Basically it consists of a series of filled circles that follow each other on a freeform motion path and then repeat when each circle reaches the end.

The beginning and end of the pipe run have a small rectangle on the top layer that obscures the circles so that they aren't visible until they start to move and can't be seen jumping back to the start once they reach the end.

By adjusting the colour of the circles relative to the colour of the pipe, you could make them only just visible so that they don't stand out too much, but just enough to show the flow.

In order to ensure that the motion paths and circles are correctly aligned, all you have to do is to create the first one and then copy and paste it to create the remainder. Finally, select all of the circles and align then by centres, both horizontally and vertically so that they sit exactly on top of one another.

The reason why I chose a circle is because it looks the same from any angle and so it doesn't need to be rotated to appear correctly aligned with its direction of flow through the pipe.

Hope this helps, but if you have any further queries, just get back to me here.