int counter;          // count 200 samples
int minValue;
int maxValue;

void setup() 
{
  Serial.begin(115200);
  Serial.println( "The sketch has started");

  counter = 0;                  // start at the begin
  minValue = maxValue = SensorValue(); // give them a value from the sensor to start with
}

void loop() 
{

  int newValue = SensorValue();
  if( newValue > maxValue)
  {
    maxValue = newValue;
    Serial.print( "▲");         // this is a UTF-8 character
  }
  else if( newValue < minValue)
  {
    minValue = newValue;
    Serial.print( "▼");         // this is a UTF-8 character
  }
  else
  {
    Serial.print( "─");         // this is a UTF-8 character
  }

  counter++;
  if( counter == 200)
  {
    Serial.println();
    Serial.print( "Minimum value: ");
    Serial.print( minValue);
    Serial.print( ", ");
    Serial.print( "Maximum value: ");
    Serial.println( maxValue);

    counter = 0;                // start at the begin
    minValue = maxValue = SensorValue(); // give them a value from the sensor to start with
  }
  delay( 50);
}


int SensorValue()
{
  // This is no fun:
  //   return random( -20000, +20001);

  // This is more fun:
  return( random( -32, 32) * random( -32, 32) * random( -32, 32));
}