A rendering for an eerie obelisk.

techno_obelisk.ino

#include <Adafruit_NeoPixel.h>

#define PIN 1

//single pixel, v2 Flora RGB NeoPixel, so GRB bitsream at 800 khz
Adafruit_NeoPixel strip = Adafruit_NeoPixel(4, PIN, NEO_GRB + NEO_KHZ800);

// assuming we have adafruit gemma v2
// http://adafru.it/1222
// assuming we have four fiora RGB neopixels
// http://adafru.it/1260

// set current values
int gValues[] = {30, 20, 10, 0};
// set current velocity
int gVelocity[] = {-10, 10, 10, 0};
int delayMs = 300;
int delta = 1;
int gMax = 55;
int gMin = 0;

void setup()
{
  strip.begin();
  strip.show(); //initialize all pixels to off
}

// keep fading values in and out
void loop()
{ 
  updateValues();
  renderValues();
  delay(delayMs);
}

// update values
void updateValues() {
  for (int i=0;i<4;i++) {
    gValues[i] = gValues[i] + gVelocity[i];
    
    if (gValues[i] >= gMax) {
      gVelocity[i] = -gVelocity[i];
    }
    
    if (gValues[i] < gMin) {
      gValues[i] = gMin;
      gVelocity[i] = -gVelocity[i];
    }
  }
}

// set green only, to current gValue for node
void renderValues() {
  for (int i=0;i<4;i++) {
    strip.setPixelColor(i,0,gValues[i],0);
  }
  strip.show();
}