Phi.c
From Organic Design wiki
// Calculate Phi from pi
double Phi = 0;
int n, i = -1;
for (n = 0; n < iterations; n += 2) {
Phi += pow(PI/5,n) / factorial(n) * (i = -i);
}
Phi *= 2;
// Calculate Phi from pi
double Phi = 0;
int n, i = -1;
for (n = 0; n < iterations; n += 2) {
Phi += pow(PI/5,n) / factorial(n) * (i = -i);
}
Phi *= 2;