It crashes on my PC (Win Me, beta9.icl) if sin(X) is negative.
So, the following code also crashes.
//-----------
#declare X = .1;
#while(X <= 4)
sphere { <X, (-0.4)^(-0.4), -.1>, .05 pigment { rgb 1 } }
#declare X = X+.1;
#end
//-----------
In this case, POV-Ray should stop the rendering with an error message.
R. Suzuki
