  In this exploratory note we ask the question of what a measure of performance
for all tasks is like if we use a weighting of tasks based on a difficulty
function. This difficulty function depends on the complexity of the
(acceptable) solution for the task (instead of a universal distribution over
tasks or an adaptive test). The resulting aggregations and decompositions are
(now retrospectively) seen as the natural (and trivial) interactive
generalisation of the C-tests.
