text: #!/usr/bin/python
  
  # Simple strand test for Adafruit Dot Star RGB LED strip.
  # This is a basic diagnostic tool, NOT a graphics demo...helps confirm
  # correct wiring and tests each pixel's ability to display red, green
  # and blue and to forward data down the line.  By limiting the number
  # and color of LEDs, it's reasonably safe to power a couple meters off
  # USB.  DON'T try that with other code!
  
  import time
  from dotstar import Adafruit_DotStar
  
  numpixels = 230 # Number of LEDs in strip
  
  # Here's how to control the strip from any two GPIO pins:
  datapin   = 17
  clockpin  = 27
  strip     = Adafruit_DotStar(numpixels, datapin, clockpin)
  
  # Alternate ways of declaring strip:
  # strip   = Adafruit_DotStar(numpixels)           # Use SPI (pins 10=MOSI, 11=SCLK)
  # strip   = Adafruit_DotStar(numpixels, 32000000) # SPI @ ~32 MHz
  # strip   = Adafruit_DotStar()                    # SPI, No pixel buffer
  # strip   = Adafruit_DotStar(32000000)            # 32 MHz SPI, no pixel buf
  # See image-pov.py for explanation of no-pixel-buffer use.
  # Append "order='gbr'" to declaration for proper colors w/older DotStar strips)
  
  strip.begin()           # Initialize pins for output
  strip.setBrightness(64) # Limit brightness to ~1/4 duty cycle
  
  # Runs 10 LEDs at a time along strip, cycling through red, green and blue.
  # This requires about 200 mA for all the 'on' pixels + 1 mA per 'off' pixel.
  
  head  = 0               # Index of first 'on' pixel
  tail  = -10             # Index of last 'off' pixel
  color = 0xFF0000        # 'On' color (starts red)
  
  while True:                              # Loop forever
  
  	strip.setPixelColor(head, color) # Turn on 'head' pixel
  	strip.setPixelColor(tail, 0)     # Turn off 'tail'
  	strip.show()                     # Refresh strip
  	time.sleep(1.0 / 50)             # Pause 20 milliseconds (~50 fps)
  
  	head += 1                        # Advance head position
  	if(head >= numpixels):           # Off end of strip?
  		head    = 0              # Reset to start
  		color >>= 8              # Red->green->blue->black
  		if(color == 0): color = 0xFF0000 # If black, reset to red
  
  	tail += 1                        # Advance tail position
  	if(tail >= numpixels): tail = 0  # Off end? Reset
  