Strange surface generation by jsjslim

// Generates the parametric surface float** calcShape2(int numVerts) {     float **vertices = (float**)malloc(sizeof(float*)*numVerts*numVerts);     int i=0;     float du = (M_PI*2)/numVerts;     float dv = (M_PI*2)/numVerts;     double x,y,z;     int u,v=0;     for (u=0; u<numVerts; u++)     {         for (v=0; v<numVerts; v++)         {             vertices[i] = (float*)malloc(sizeof(float)*3);             vertices[i][0] = (u*du)*cos(v*dv)/(2*M_PI);             vertices[i][1] = (u*du)*sin(v*dv)/(2*M_PI);             vertices[i][2] = (u*du)*sin(v*dv)*sin(u*du)/(2*M_PI);             i++;         }     }     return vertices; } // This goes into the display function for (i=0; i<pow(numVerts,2)-3; i+=3) {     glBegin(GL_POLYGON);         glVertex3fv(vert[i]);         glVertex3fv(vert[i+1]);         glVertex3fv(vert[i+2]);         glVertex3fv(vert[i+3]);     glEnd(); }