Modifying void colorWipe's code

I’m trying to modify a part of the strandtest code so that it can do something kind of like the below picture. I want to have one string of LEDs in a circle programmed to light up starting at one point, then have the very next points at either side come on (while keeping the previous one on, just like the colorWipe originally does), and continue until they meet again at the opposite end of the circle. How would this code be modified to do that?

void loop() {
  // Some example procedures showing how to display to the pixels:
  colorWipe(strip.Color(255, 0, 0), 50); // Red
  colorWipe(strip.Color(0, 255, 0), 50); // Green
  colorWipe(strip.Color(0, 0, 255), 50); // Blue

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);;

LED example.png

int startpixel = Whatever;
strip.setPixelColor((startpixel, c);  // first pixel;
for(uint16_t i=1; i<=strip.numPixels()/2; i++) { // half as many loops
    strip.setPixelColor((startpixel+i) % strip.numpixels, c);  //one direction, with wrap
    strip.setPixelColor((startpixel+strip.numpixels-i) % strip.numpixels, c); // other direction.;

So if you started at 10 in a circle of 12, the loop should do 11, 12, 0, 1, 2, 3
and 9 ((10+12 -1) % 12), 8, 7, 6, 5, 4

I am confused. ACrespin124 wrote "...and continue until they meet again at the opposite end of the circle" but the attached image does NOT meet at the opposite end of the circle. Implementing code to duplicate the image would require two speeds, one for clockwise and one for counterclockwise (anticlockwise). What is really wanted?

My objective was basically what he was trying to help me achieve. I'm not going for exactly what the picture describes; the start and end point are opposite from each other on the circle in my instance, I just needed a picture to sort of describe what was happening. I want them to move evenly until they meet at the opposite end of their relative starting point.