Knotilus

What Knotilus is

Ten numbers, three chains and one shared value make up Knotilus, an addition puzzle built on Fibonacci-style runs. From the day's pool you must form three increasing chains of four, where each term from the third on equals the two before it added together. The chains overlap in exactly one number, the knot, and every other number appears once.

How a round works

Tap four numbers to enter a run; it joins your list once the fourth goes in. Several valid runs hide in any puzzle (the rules put it at four to ten), but only one trio uses every number with the knot as the lone overlap. Pick three runs from your list to submit; the clock stops once the right three are chosen, and any valid runs you missed are then shown. Tapping a lock at the top left gives away one run of the answer. Easy mode adds visual guides that Hard takes away, and a level setting picks the size of the number pool. A sample board teaches the knot logic first, and an archive calendar holds earlier days.

Good if you like…

• Equations: Equations also groups numbers by arithmetic, sorting a grid into sets of three in which two numbers make the third, but it allows multiplying and powers and has no shared knot.
• Summle: Summle chains sums too, reaching a target number within five steps while reusing subtotals, whereas Knotilus has no target, only the rule that each term adds up the two before.
• Sequences: Sequences is about number patterns as well, but you work out the rule in a single run and type the term that follows, with three attempts, instead of building three runs at once.
• Buzzled: Buzzled is another sum puzzle on a small board: you flip numbered hexagons between two colors until the picked color in every row reaches its target, a balancing job rather than chain building.

What we checked

• Loads: yes, over HTTPS (opened Nov 5, 2026).
• On a phone: the page sets a mobile viewport and fits a phone screen without sideways scrolling.
• Embedding: the game’s site allows being shown inside other sites.
• Account: none needed for the daily puzzle.
• Past puzzles: an archive of earlier days is available.