After the urns have been shuffled, one of them is better for you because it has more
{% if participant.group_assignment == C.GROUP_TRIANGLE %}
{{subsession.session.winning_color_triangle}}
{% elif participant.group_assignment == C.GROUP_SQUARE %}
{{subsession.session.winning_color_square}}
{% endif %} marbles.
Because the urns are shuffled at the beginning of a block and the colours of the marbles are hidden,
you don't know for sure which urn is better.
But because you can always see the colour of the marble that is drawn from the
urn you choose, and because the urns are not shuffled during the 4 rounds in a block, you can
try to find out in those 4 rounds which urn has more marbles of your winning colour.