The Idol-Haul of Ketterwy Temple

Deep in the jungle, the Ketterwy Temple has begun to sink into its own foundations. The Guild of Reclaimers has bought the right to drag its stone idols out before the roof comes down. Only one tunnel leads out, and it is barely wide enough for a single log-sled. The idols are hauled out on these sleds in the exact order they are pried from their niches.

The haul-master loads the sleds by one fixed rule:

• Idols are taken strictly in the given order. No idol is ever skipped, held back, or moved ahead of another.
• An idol goes onto the sled currently being loaded if the sled's total weight, with that idol added, stays at or below capacity.
• Otherwise, the current sled is sent down the tunnel and a new, empty sled is started with that idol on it.
• When the idols run out, the sled being loaded is sent as well, provided it carries at least one idol.

Write loadSleds(weights, capacity).

• weights is a list of positive integers. Each one is the weight of an idol, in the order the idols are recovered. It may be empty.
• capacity is a positive integer. Every value in weights is at most capacity.

Return a list of sleds in the order they are sent. Each sled is a list of the weights it carries, in loading order. If weights is empty, return an empty list.