A program for create any kind of surfaces in 3d.
Figures in rectangular z=f(x,y)
        and spherical coordinates sx=f(a,t);sy=f(a,t);sz=f(a,t)
        Constants: pi and any int/floating number
        Variables: x y   a t u v
        Operators:  + - * /   > | etc.
        Functions:  if(exp,exp1,exp2)
        sin() cos() tan() asin() acos() atan()
        sinh() cosh() tanh() log() ln() rand()
        exp() abs() sqrt() pow(base,exponent)
        For anaglyph use red-cyan glasses
        Open any kind of image and use it for texture.
        The instructions to program;
        // For coments
        start - To clear the scene. Is the first intruction.
        A program without start will be added to the scene. See sample 8\
        z=f(x,y) - A surface in rectagular coordinates. Sample 1
        For surface in spherical coordinates define first the range of a and t:
        sa=0,2*pi and st=0,pi
        Then the surface. Sample 2:
        sx=f(a,t), sy=f(a,t), sz=f(a,t)
        The surface can be moved in the three axis:
        dx= dy= dz= See Sample 3.
        And rotated in the three axis:
        rx= ry= rz= See sample 4.
        For planes you may use z=2 or the instruction:
        plane(width,height,rx,ry,rz,dx,dy,dz) See sample 5
        See Samples > 5 for general application.
       trian(width,height,rx,ry,rz,dx,dy,dz) for right triangles. See samples 17, 18
        cube(width,height,rx,ry,rz,dx,dy,dz) for cubes. See sample 23
        cyli(width,height,rx,ry,rz,dx,dy,dz) for cylinders. See sample 26
        cone(r1,r2,height,rx,ry,rz,dx,dy,dz) for cones. See sample 28
        sphe(width,height,dx,dy,dz) for spheres. See sample 24
        pyra(width,height,rx,ry,rz,dx,dy,dz) for pyramids. See sample 25
        para(width,height,alfa,rx,ry,rz,dx,dy,dz) for parallelepiped. See sample 31
para2(width1,width2,height,rx,ry,rz,dx,dy,dz) for parallelepiped2. See sample 36
        para3(width1,width2,height1,height2,rx,ry,rz,dx,dy,dz) for parallelepiped3. See samples 43,44
        light(width,height,rx,ry,rz,dx,dy,dz) for ligth. See sample 42
        trape(width,height,bl,br,rx,ry,rz,dx,dy,dz) for trapezium. See sample 40
        bl and br are the bases of the left and right triangles
        For repetitive actions use do - enddo. See sample 9, 14, 15 and 16
       For textures use: texture(n) being n between 1 and 12.
       9 correspond to the image previously open. See samples 18,20 and 21