Fable
Cross the stone bridge first, then take the windy snowy mountain pass
The post station took on a new messenger, A Nan. The stationmaster was desperate for hands, so on the first day he sent him over snowy mountains, across a suspension bridge, and to find the road at night. A Nan had memorized the map, but at the mountain pass he mistook the sound of wind for the sound of a river, went half a day off course, and the letters got wet in the snow.
Some said Anan had no talent. The old courier was not in a hurry and took him back to flat roads. In the first week he practiced only reading road signs and milestone stones, in the second week he practiced identifying mud prints after rain, and only in the third week did he cross narrow bridges, after which night roads, wind and snow, and carrying loads were added.
At first Anan felt it was too slow. But on flat roads he learned to match forks with village names, on rainy days he learned to judge whether wheel ruts were fresh or old, and on bridges he learned to allocate foot strength. Each layer left a handhold for the next.
The stationmaster once wanted to skip a level and have him deliver urgent letters directly. The old courier stopped him: it is not that hard problems cannot be practiced, but that you must press on them only after the earlier capabilities are solid. If you pile all the difficulties together from the start, when you fail you cannot even see where the mistake is.
Two months later, Anan crossed the snow mountain again. He first confirmed the entrance by the milestone, then judged the snow hollows by the wind direction, and before crossing the bridge moved the letter pouch to the leeward side. That trip the letter arrived a moment late, but intact.
The stationmaster initially thought that as long as the difficult road was cut shorter, it would be fine, so he had A Nan walk a short stretch of snowy mountain every day. But A Nan could not yet reliably recognize even ordinary road signs, and would panic even on a short snowy road. If difficulty is divided only by distance, not by the growth of ability, it is still pushing people into a pit.
The old courier set a passable threshold at every stage. Only after the road signs were read accurately did he add rain; only after the rainy road was stable did he add the narrow bridge; only after the narrow bridge was handled calmly did he add night. Each time, Anan faced something a little harder than yesterday, but never so hard as to be completely out of control. Half a year later, when he walked the snow mountain again, he did not rely on rote memorization of the route, but carried up the skills he had built layer by layer. The stationmaster later applied this training method to all newcomers. Newcomers were no longer scared off by the high mountain on day one, nor did they stay forever on flat ground. Task difficulty rose like steps, so the skills learned could catch the next level.
The station later reordered the training manual: start with simple, clean, correctable routes, then gradually add noise, danger and combined tasks. A good courier is not forged by being hit with hard problems, but by connecting each capability to the next in the right order.