set_link("from", ValueNode_Const::create(Real(1.0)));
set_link("to", ValueNode_Const::create(x.get(Real())));
set_link("step", ValueNode_Const::create(Real(1.0)));
set_link("from", ValueNode_Const::create(Real(1.0)));
set_link("to", ValueNode_Const::create(x.get(Real())));
set_link("step", ValueNode_Const::create(Real(1.0)));