This is an entry-level question, but I'm interested in designing a draggable problem that asks students to classify items that do not necessarily exclusively belong to any given subset. In my below MWE, "orange" can/should be classified as both a color and a fruit. Perhaps there is a mechanism to repopulate the full set after an item is dragged to a bucket?
DOCUMENT();
loadMacros('PGstandard.pl', 'PGML.pl', 'draggableSubsets.pl', 'PGcourse.pl');
$draggable = DraggableSubsets(
[ 'orange','blue','apple', ],
[ [], [ 0,1 ], [ 0,2 ] ],
DefaultSubsets => [
{ label => 'Drag each of the the below words to classify them as a color or a fruit.', indices => [ 0 .. 2 ] },
{ label => 'Color', indices => [] },
{ label => 'Fruit', indices => [] },
],
AllowNewBuckets => 0,
);
BEGIN_PGML
[_]{$draggable}
END_PGML
ENDDOCUMENT();