//Loop all layers in current project.
doc -e L 
{
  draw -l {-1, -1, 1, 1};  //draw a line object from the point(-1,-1) to the point (1,1) on the current layer. 
};

create myyeqx -f 100 "x";  //100 points on y=x curve
doc -e P
{
  plotxy myyeqx 200 ogl:=1;  //200:Line, Put rescale:=1 to rescale
};