Grouped Continuous Nice Loop
Treat candidate groups as nodes in a continuous alternating loop to derive eliminations from adjacent nodes.
All candidates have been entered in the empty cells.
On a solid link, one false end makes the other end true. On a dashed link, one true end makes the other end false. Following the closed loop makes at least one end of every dashed link true. Therefore, remove candidates 2 and 7, which conflict with both ends of their corresponding dashed links.