%
% stack: source-data
%
% remove values from node
%
!altered

sel@
_\ @^*Values

countup
2 div
{
 pop
%
% stack: val-data val-name
%
 dup "_" atleft
 {
  pop2
 }
 {
  
%%%  false exch _\ @!Valued
%%%  pop

  _altered
  *valpress
  !altered
%
% stack: val-data val-name
%
  pop2
 } ifelse
%
% stack:
%

} for