Mintonette: 250 Medium to Hard Logic Puzzles 7x7 - Mindful Puzzle Books - Bog

The goal is to connect circles in pairs by drawing a line that goes horizontally and vertically through the centers of cells. Lines cannot touch or cross themselves or each other. If a circle contains a number, it represents the number of turns for the line between two circles. If two circles have no number, a line may make any number of turns between circles. All cells must be used by the lines, and each circle must be connected to another circle.