Unity 2018.3.2f1
Im unable to make subtraction of two cubes.
visual glitches appear:

distance function:
inline float DistanceFunction(float3 pos)
{
float x = Box(pos,float3(1,1,1));
pos-= float3(0.5,0.5,0.5);
float y = Box(pos,float3(1,1,1));
//float v = Sphere(pos, 1); (uncoment and change -x to -v below to see it working with sphere)
return max(y,-x);
}