Gyroid minimal surface

Describe in math:
F()=cos(x) * sin(y) + cos(y) * sin(z) + cos(z) * sin(x)
[x]: -4 , 4
[y]: -4 , 4
[z]: -4 , 4

Describe in math:
F()= cos(x) * sin(y) + cos(y) * sin(z) + cos(z) * sin(x)
[x]: -4 , 4
[y]: -4 , 4
[z]: -4 , 20