Obstacles
Eight boards from 5×5 to 7×7 with 3 to 8 threads. Some cells are sunken: those are holes in the cloth.
Leave a hole empty — threads can’t go through it, and you don’t need to cover it. Every other cell still has to be filled. Holes split the board into lanes and pockets, which changes where threads can go.
Look at the cells next to holes first. An empty cell with a hole on one side and the border on another has very few ways in, so it often decides which thread passes there. Most levels here are gentle, and the last one is a real test. More in the obstacles guide and avoiding empty pockets.