Four Loops in a Row
Solve the four grids in a row and the corner patterns stop needing thought. Keep the crosses small, so that they do not hide the dots on a quarter-page grid.
What Each Level Trains
Easy sheets train counting, Medium sheets the reading of each number with its corners, and Hard sheets the habit of testing a line lightly before drawing it for good.
Toward the 10x10 Grids
Once the Hard sheets of four come easily, the single 10x10 grids bring a much larger loop. The 7x7 Slitherlink page has this size printed one grid per page.