 #define GREEN 5
 #define BLUE 6
 
+// pi and 2*pi
+#define PI  3.141592654
+#define PI2 (PI*2)
+
 // network stuff
 #define PORT 8467
 #define BUFFSIZE 17
+
 byte mac[] = {0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02};
 byte ip[] = {192, 168, 1, 4};
 byte gateway[] = {192, 168, 1, 253};
 byte subnet[] = {255, 255, 255, 0};
+
 EthernetServer server = EthernetServer(PORT);
 
 /* 

 * y(x):=A*sin(B/c*x+D)+E
 */
struct colourFunction {
  unsigned char a;
  unsigned char b;
  unsigned char c;
  float bc; // bc = B / C
  unsigned char d;
  unsigned char e;
};

/*

 * the time between each iteration.
 */
struct colourSettings {
	unsigned char waittime;
	struct colourFunction red;
	struct colourFunction green;
	struct colourFunction blue;
};


